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Antimony selenide (Sb2Se3) is regarded as a next‐generation material for high‐efficiency photovoltaic applications due to its favorable bandgap, high absorption coefficient, carrier mobility, and stability. Nonetheless, cadmiun sulfide (CdS) has low short‐wavelength transmittance, which limits photon utilization, and the suboptimal band alignment in the CdS/Sb2Se3 heterojunction causes significant interface recombination. In this study, a simple lithium‐ion doping method is presented and report the dual enhancement effects of lithium ions on CdS and Sb2Se3 layers for the first time. Lithium ions improve the CdS layer by allowing for larger grain sizes, reduces roughness, and increase transmittance in the electron transport layer. At the same time, lightweight Li ions diffuse more easily through the interface into the Sb2Se3 layer, resulting in improved orientation, lower defect density, and a longer carrier lifetime. Furthermore, doping with Li ions changes the band alignment of the CdS/Sb2Se3 junction from a “cliff‐like” to a “spike‐like” configuration, improving carrier transport and reducing carrier recombination near the interface. Ultimately, due to the benefits of Li‐ion doping, the champion device obtained have a VOC of 0.462 V, a JSC of 30.86 mA cm−2, an FF of 65.46%, and an efficiency of 9.33%, representing a 15.8% increase over the undoped device. [ABSTRACT FROM AUTHOR]

In this study, we synthesized MOF/COF hybrid material (NH2-MOF-5/MCOF) by integrating NH2-MOF-5 (Zn) with a melamine-based COF (MCOF) to target the photocatalytic degradation of methylene blue (MB) dye. Characterization using SEM, XRD, XPS, FT-IR, and UV-DRS confirmed the synthesized MOF/COF hybrid's exceptional photocatalytic performance under visible light. The addition of H2O2 significantly enhanced the photocatalytic degradation, achieving removal rates of 90%, 92%, and 57% for 11.75 mg L−1, 30 mg L−1, and 83 mg L−1 of MB, respectively. Kinetic studies revealed first-order kinetics, with a rate constant nearly 3.5 times higher with added H2O2. We proposed a comprehensive photocatalytic mechanism elucidated through energy band structure analysis and scavenger tests. Our findings revealed the formation of a heterojunction between NH2-MOF-5 and MCOF, which mitigates electron–hole recombination, with ∙OH identified as the principal species governing methylene blue degradation. Moreover, the NH2-MOF-5/MCOF hybrid displayed excellent reusability and chemical stability over six cycles. Notably, this H2O2-assisted hybrid material demonstrated the removal of 99% of ibuprofen, a pharmaceutical drug, showcasing its broad applicability in removing organic contaminants in aqueous solutions, thereby holding great promise for wastewater treatment. [ABSTRACT FROM AUTHOR]

Copper based sulfur compounds have excellent optoelectronic properties which can be regulated through chemical doping, and are the candidate materials for solar cells, photocatalysis and other fields. The crystal models of CuFe(SxSeyTe1-x-y)2 (x = 0.125,0.25,0.25,0.5; y = 0.125,0.25,0.5,0.25) are established, and the energy bands and density of states of CuFe(SxSeyTe1-x-y)2 are calculated using first principles. The analysis results show that as the doping of S atoms increases, the lattice constants a and b gradually increase, while the lattice constants c and cell volume V become smaller and smaller; As the doping of Se atoms increases, the lattice constants a and b gradually increase, while the lattice constant c and cell volume V become smaller and smaller. The valence band top and conduction band bottom of CuFe(SxSeyTe1-x-y)2 (x = 0.125,0.25,0.25,0.5; y = 0.125,0.25,0.5,0.25) are at the same point G. It can be explained that CuFe(SxSeyTe1-x-y)2 is a direct bandgap semiconductor, and the bandgap widths of the selected crystal structures corresponding to the values of x and y are approximately 0.98, 0.97, 0.91 and 0.98 eV, respectively. The diagram for the density of states has peaks on both sides of the Fermi level, and other peaks in the density of states figure also correspond to the band graph. The size and trend of the peaks reflect the strength of electron delocalization. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, we report the design and fabrication of self-powered binary response PDs based on II-type heterostructures consisting of SnS x nanoflakes (NFs) and rutile TiO 2 nanorod arrays (NRs). The TiO 2 NRs effectively block light with wavelengths below 400 nm from reaching SnS x. Under 385 nm light, the photoelectrons in TiO 2 recombine with holes in SnS x at the interface due to the energy band bending, resulting in a positive photocurrent. Under 410 nm light, the photoelectrons in SnS x and the photogenerated holes in TiO 2 accumulate at the interface, overcoming the interfacial potential barriers induced by the higher Fermi levels of SnS x and inducing a negative photocurrent. Based on the bipolar response, the dual-band imaging capability without external filters and the light-encrypted OR, AND, and NOT logic gates using a single device are demonstrated. This work provides a blueprint for the development of multifunctional self-powered PDs that can simplify system architecture, reduce the energy consumption, and improve accuracy for applications, such as visual systems, light-controlled logic circuits, and encrypted optical communications. [ABSTRACT FROM AUTHOR]

In order to deeply investigate the dielectric and ferroelectric photovoltaic properties of BiFeO3 (BFO) thin films, the Pt/BFO/La 0. 5 Sr 0. 5 CoO3 (LSCO) heterostructure ferroelectric capacitor grown on (001) SrTiO3 (STO) substrate is successfully fabricated by off-axis magnetron sputtering. The X-ray diffraction (XRD) and Phi scanning results show that the STO-based BFO and LSCO films are both (001) epitaxial structure. Although the BFO ferroelectric film exhibits an obvious dielectric dispersion phenomenon, a remarkable ferroelectric photovoltaic performance is obtained with open circuit voltage ( V OC ) of 0.38 V and short-circuit current ( J SC ) of 0.23 mA/cm2, respectively. With increasing test temperatures, V OC decreases slowly and then rapidly, while J SC increases rapidly and then decreases. At a critical temperature of 80∘C, the BFO ferroelectric film exhibits a faster photovoltaic response, in which the values of V OC and J SC are about 0.19 V and 0.28 mA/cm2, respectively. Moreover, the energy band analysis indicates that a large work function difference (∼ 1 eV) between LSCO and Pt leads to a strong built-in electric field in the BFO film, which is beneficial to separate the photo-generated carriers and improve ferroelectric photovoltaic effect. In all, this study not only shows that BFO is an excellent and environmentally friendly photovoltaic candidate material, but also provides a practical strategy for improving the performance of BFO ferroelectric photovoltaic devices. [ABSTRACT FROM AUTHOR]

As an effective and robust wastewater treatment method, a photocatalytic fabric featuring the Z-scheme heterojunction was developed by combining a Co/Fe bimetallic metal–organic framework (NH2-MIL-88B) and Ag3PO4 catalysts. This study reveals that by controlling the Co/Fe molar ratio of NH2-MIL-88B (Co/Fe) (noted as MILx), the nanocrystal structures of the bimetallic MILx and the associated heterojunction with Ag3PO4 (noted as Ag/MILx) were manipulated to perform higher adsorption and accelerated photocatalytic reaction for removing Rhodamine B (RhB) pollutant in water. Photoelectrochemical investigation and scavenging experiments revealed that heterojunction catalysts with bimetallic MILx (Ag/MILx) followed the charge transfer pathways of the Z-scheme, facilitating the generation of •O2– by increasing the conduction band energy position. As a result, at the optimal Co/Fe molar ratio of 0.2 in the heterojunction cocatalyst, RhB adsorption performance was improved by 28% and the RhB degradation was accelerated by 1.5 times compared to the heterojunction formed with Ag3PO4 and single-metal NH2-MIL-88B (Fe). The material developed in this study offers a unique advantage compared to other catalytic materials by strategically utilizing both crystal defects and heterojunction design to enhance the photocatalytic performance. This study is significant in providing crucial empirical evidence that is insightful for designing an effective photocatalytic self-cleaning material composed of complex cocatalytic nanocrystals for enhanced wastewater remediation. [ABSTRACT FROM AUTHOR]

In this work, a high-k In0.53Ga0.47As silicon-on-insulator FinFET (InGaAs–SOI–FinFET) is presented for high-switching and ultra-low power applications at 7 nm gate length. Indium Gallium Arsenide (InGaAs) is a compound semiconductor that has gained attention in the field of semiconductor devices, including FinFETs. The incorporation of InGaAs in proposed FinFETs introduces several advantages, making it an attractive material for certain applications. InGaAs–SOI–FinFET performance has been observed and found high electron mobility, improved On-Current performance (ION), drain current (IDS), transconductance (gm), energy bands, lower subthreshold swing (SS), electric field, surface potential, and better short-channel behaviour. All the results of InGaAs–SOI–FinFET have been simultaneously compared with SOI-FinFET and conventional FinFET (C-FinFET). Incorporating InGaAs in the channel with high-k gate material enhances the drain current by ⁓75% and ⁓77% in the proposed device compared to the other two counterparts. Owing to the higher drain current in the InGaAs–SOI–FinFET, other parameters have also been improved, which leads to higher performance applications.

The present article deals with the issue of thermodynamic and electro-kinetic aspects of diffusion and migration (charge transfer) of electrons (e) and holes (h) across an n-type-p-type junction under bias and a photovoltaic cell under illumination from the pedagogical motivation. From the equality of the electrochemical potential of e and h on both sides, it follows that the alignment of the Fermi energy levels gives rise to the separation of the energy bands, causing the build-up of a reversible contact potential. Physical significance of the contact potential has been extensively discussed. Under forward bias, diffusion of the majority carrier electrons in the n-type side has been detailed with simultaneously recombining through the junction "p/n" (p ← n) to the p-type side. Moreover, diffusion of the majority holes in the p-type side has been dealt with in a similar way but in the opposite direction. As a result of under forward bias, the overall resulting current flows in the direction from the p-type to the n-type side. Under forward bias, the contribution of the diffusion current by the majority carriers far outweighs the contribution of the drift current by the minority carriers. In contrast, under reverse bias, the minority electrons created within a diffusion length of e of the transition region on the p side can diffuse to the junction "n/p" (n ← p), and finally, they are swept down before recombining due to the migration (charge transfer) across the junction "n/p" (n ← p) in the direction opposite to the electric field, from p to n, that is, without any barriers. Furthermore, diffusion of the minority holes created within the transition region on the n side to the junction "p/n" (p ← n) has been dealt with likewise across the junction "p/n" (p ← n), but in the direction of the electric field, from n to p. As a result of under reverse bias, the overall resulting current flows in the direction from the n-type to the p-type side. Under reverse bias, the reverse drift current by the minority carriers dominates the diffusion current by the majority carriers. The derivation of a diode equation with bias and another modified equation under illumination necessitates a deep understanding of the Fick's first law and modified Fick's second formula. The photo-driven voltaic cell with illumination delivering electric power to the external load is clearly distinguished from the externally driven junction with bias. The delivered current enhanced by the incident light radiation is almost exclusively determined by the drift current by the minority carriers e and h due to their migration (charge transfer) in the direction from the n-type to the p-type. The delivered photovoltage runs in the direction as in the forward bias (from p to n). The photo-enhanced reverse drift current dominates the diffusion current by the majority carriers since the effect of the light quanta radiation is minimal on the change in the majority carrier concentration. Finally, some quizzes are raised with their answers to them, so that the readers facing the problems are motivated to solve them in the instructive perspectives. [ABSTRACT FROM AUTHOR]

In the past several decades, Photoelectrochemical (PEC) sensing still remains a great challenge to design highly‐efficient semiconductor photocatalysts via a facile method. It is of much importance to design and synthesize various novel nanostructured sensing materials for further improving the response performance. Herein, we present an In2O3/In2S3 heterostructure obtained by combining microwave assisted hydrothermal method with S‐induced phase change, whose energy band and electronic structure could be adjusted by changing the S content. Combining theoretical calculation and spectroscopic techniques, the introduction of sulfur was proved to produce multifunctional interfaces, inducing the change of phase, oxygen vacancies and band gap, which accelerates the separation of photoexcited carriers and reduces their recombination, improving the electronic injection efficiency around the interface of In2O3/In2S3. As anticipated, an enhanced glucose response performance with a photocurrent of 0.6 mA cm−2, a linear range of 0.1–1 mM and a detection limit as low as 14.5 μM has been achieved based on the In2O3/In2S3 heterostructure, which is significant superior over its pure In2O3 and S‐doped In2O3 counterparts. This efficient interfacial strategy may open a new route to manipulate the electrical structure, and energy band structure regulation of sensing material to improve the performance of photoelectrodes for PEC. [ABSTRACT FROM AUTHOR]

Single Ti3C2Tx MXene (MTO) materials are not suitable for electromagnetic (EM) wave absorption due to their high conductivity and impedance mismatch. To address this issue, we ingeniously took advantage of easily oxidized characteristics of Ti3C2Tx MXene to establish structural defects and multiphase engineering in accordion-like TixO2x−1 derived from Ti3C2Tx MXene by a high-temperature hydrogen reduction process for the first time. Phase evolution sequences are revealed to be Ti3C2Tx MXene/anatase TiO2 → Ti3C2Tx MXene/rutile TiO2 → TixO2x−1 (1 ≤ x ≤ 4) during a hydrogen reduction reaction. Benefiting from conductance loss caused by hole motion under the action of an external electric field and heterointerfaces caused by interfacial polarization, the impedance match and EM attenuation capability of accordion-like TixO2x−1 absorbers derived from Ti3C2Tx MXene are superior to that of pristine Ti3C2Tx MXene/TiO2 materials. Additionally, simulated whole radar cross section (RCS) plots in different incident angular of the Ti3C2Tx MXene/rutile TiO2 product are lower than −20 dBm2, and the minimum RCS value can reach −43 dBm2, implying a great potential for practical applications in the EM wave absorption. Moreover, the relationship among charges, defects, interfaces, and EM performances in the accordion-like TixO2x−1 materials is systematically clarified by the energy band theory, which is suitable for the research of other MXene-derived semiconductor absorbing composites.

In order to study the wave scattering problem of Bernoulli-Euler beam in the symplectic dual mechanics system, the Hamiltonian dual equation of Bernoulli-Euler beam was proposed by constructing Lagrange multipliers to release functional constraints and introducing dual variables. The scattering matrix of the end scatterer was obtained by combining the eigenvector expansion method, the symplectic Gram-Schmidt orthogonal algorithm, and the precise integral method to strip the stopband part of the energy band structure of the Bernoulli-Euler beam. The results show that the state vector of the Bernoulli-Euler beam in the symplectic system is composed of a pair of passband eigenvectors and a pair of stopband eigenvectors. The scattering matrix is a first-order unitary matrix, and the power flow of the incident wave is equal to the power flow of the reflected wave, which satisfies the power flow conservation. [ABSTRACT FROM AUTHOR]

SiC/Si and GaN/Si heterojunction technology has been widely used in power semiconductor devices, and SiC/Si VDMOS and GaN/Si VDMOS were proposed in our previous paper. Based on existing research, breakdown point transfer technology (BPT) was used to optimize SiC/Si VDMOS. Simulation results showed that the BV of the SiC/Si heterojunction VDMOS was considerably increased from 259 V to 1144 V, and Ron,sp decreased from 18.2 mΩ·cm2 to 6.03 mΩ·cm2 compared with Si VDMOS. In order to analyze the characteristics of the SiC/Si heterojunction structure deeply, the influence of the interface state characteristics of the SiC/Si heterojunction on the electrical parameters of VDMOS was analyzed, including electric field characteristics, blocking characteristics, output characteristics, and transfer characteristics. In addition, the influence of the interface state of the SiC/Si heterojunction on energy band characteristics was analyzed. The results showed that with an increase in the interfacial charge (acceptor) concentration, the p-type trap layer was introduced into the interface of the SiC/Si heterojunction, energy increased slightly, and the barrier height difference at the heterojunction increased, resulting in an increase in BV. At the same time, since the barrier height became higher, electrons did not flow easily, so Ron,sp increased. On the contrary, when a charge (donor) was introduced at the interface of the SiC/Si heterojunction, the number of electrons in the channel increased, resulting in an increase in the electron current, which is conducive to the flow of electrons, resulting in a decrease in Ron,sp. The energy band and other characteristics of devices with temperature were simulated at different temperatures. Finally, the effects of SiC/Si heterojunction interface states on interface capacitances and switching performances of VDMOS devices were also discussed. [ABSTRACT FROM AUTHOR]

This work presents the impact of barrier spacer on the structural and optical properties of strain-coupled Stranski-Krastanov (SK) on Sub Monolayer (SML) quantum dot (QD) heterostructures. Various ternary and quaternary materials have been employed as the barrier layer of SK-SML QD heterostructures. In the coupled SK-SML QDs, the residual strain propagates from the SML seed layer towards the top SK dots, introducing defects and dislocations. After employing the ternary (GaAs1-ySby) and quaternary (InxAl0.21Ga1-.0.21-xAs and In0.18Ga0.82As1-ySby) materials, the residual strain reduces, reducing the defects which thereby helps in increasing the crystalline quality of the heterostructure. Nextnano software has been used to compute the structures' strain, energy band profile, probability density functions, and emission wavelength. Two strain components, viz. hydrostatic as well as biaxial strain, have been computed and compared for all the heterostructures to understand the distribution of the strain profile. The emission wavelength is red-shifted for the SK-SML QD heterostructures with ternary and quaternary materials as a barrier layer as compared to that of the GaAs barrier. Moreover, type-I and II energy band profiles are observed for Sb-based barrier material, appropriate for various optoelectronic applications. This is a comparative study of SK-SML QDs with various barrier materials helps minimize the strain and defects and improve the device performance. [ABSTRACT FROM AUTHOR]

The blue color of sapphire is commonly related to the amount of Fe and Ti impurities replacing Al ^3+ in the Al _2 O _3 structure. Generally, the color intensity on sapphires is related to the gem deposits including the basaltic-related and metamorphic-related ones. The color of sapphires has been changed after heating under oxidizing atmosphere. However, the explanation about the color mechanism from some previous research contradicted each other and it was still wondered. For this reason, this research is focused on the role of Fe and Ti oxidation states as well as the blue color mechanism on sapphires before and after heating under oxidizing atmosphere. In this study, the sapphire samples were collected from different gem deposits including basaltic-related sapphires from Kanchanaburi province, Thailand and metamorphic-related ones from Sri Lanka before and after heating at 1100 °C under oxidizing atmosphere. As a result, the blue color on sapphires before heating can be described as a hole color center assigned to Fe ^3+ -Ti ^4+ mixed acceptor states inside an energy band gap that could receive an electron from the valence band for charge-balancing after excitation. After heating, the basaltic-related sapphires turned from dark blue to light blue and the metamorphic-related ones turned from light blue to colorless. The Fe ^3+ -Ti ^4+ mixed acceptor states were decreased because a hole color center was filled by an electron from oxygen during the heating process instead of an electron from the valence band. Therefore, it can be concluded that the blue color mechanism on sapphires before and after heating under an oxidizing atmosphere can be explained by an energy band model involving the presence or absence of Fe ^3+ -Ti ^4+ mixed acceptor states as well as a hole color center inside an energy band gap.

Metal oxide photocatalyst is a promising wastewater treatment process due to its simplicity, high efficiency, and low cost, as well as being environmentally friendly and non-energy consuming. The perovskite structure material, SrTi1−xNbxO3 (STNO) with x = 0, 0.01, 0.03, and 0.05, was successfully synthesized by the sol-gel auto-combustion method. Samples with a pure phase and cubic perovskite structure were obtained. The Rietveld refinement results showed that the lattice parameter and unit cell density increased as the Nb-doping level increased. The particle size of the STNO decreases with increasing Nb doping content. Photoluminescence was excited at 327 nm, producing violet, green, and blue emissions, while the Nb content asserts an insignificant effect on the bandgap (Eg). The Nyquist plot and Mott-Schottky analysis were used to determine the photoelectrode performance of the STNO samples. The photocatalytic activity of STNO on the decolorization of methylene blue (MB) under UV irradiation increased with increasing Nb content and optimization at x = 0.05, corresponding to the results obtained from photoluminescence, Eg, Nyquist plot, and Mott-Schottky analyses.

Surface potential pinning effect is a general rule in semiconductor materials, which can seriously affect the performance of devices. However, the surface potential pinning effect is often overlooked in the literature when studying diamond devices. In our previous work, we experimentally verified that the oxygen terminal with ketone bonds introduces an acceptor surface state, 2.22 eV above valence band maximum (VBM), into bandgap at diamond surface. Here, we further investigated the contact band diagram between metals (Au, Ag, Pt, W, and Pd) with different work function and oxygen terminated diamond using X-ray photoelectron spectroscopy. Results showed that the contact Fermi level was at 2.38 eV, 2.33 eV, 2.32 eV, 2.28 eV, and 2.29 eV above VBM, respectively. In addition, the similar symmetrical photocurrent-voltage characteristics under positive and negative bias were observed between Au–Ag and Ag–Pt electrodes deposited on the same oxygen terminated diamond plate. And the surface energy band can be restored to the similar level after destroying by hydrogen plasma or polishing. All the data above could be drawn a conclusion that the oxygen-terminal can pin the Schottky barrier height. We believe that the results obtained herein will help in the design and theoretical analysis of diamond Schottky devices. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient multifunctional electrodes on nickel foam were constructed by corrosion engineering. • The distinctive configuration of catalyst surface endows it with remarkable HMFOR performance and structural stability. • The proposed energy band theory and heterojunction structure explain the electron transport path in HMFOR. The green synthesis of 2,5-furandicarboxylic acid (FDCA), famous as a bio-based polymer monomer from the 5-hydroxymethylfurfural (HMF), offers a promising route to reduce the usage of petroleum-based polymer polyethylene terephthalate. Although the electrocatalytic preparation of FDCA rids high temperature and pressure limits, most electrocatalysts used in the HMF oxidation reaction (HMFOR) are usually fabricated in harsh conditions. Therefore, we propose a method to improve the performance of electrocatalysts in the HMFOR reaction by introducing metal salts using natural seawater as the main feedstock. The final Co-sw/NF realized a 97.4% FDCA yield and 97.3% Faraday efficiency (FE). In-situ Raman techniques identified the catalytically active species of the catalysts employed in the HMFOR process. The effect of metal salts on catalyst energy levels is discussed in detail using the ultraviolet photoelectron spectroscopy (UPS) and Tauc plot method. The adsorption performance of HMF on the catalyst was determined by calculating the d-band centers and applying open circuit potential (OCP) tests. Furthermore, we elucidate the specific mechanism in terms of electron transport pathways. [ABSTRACT FROM AUTHOR]

Photocatalytic technology driven by sunlight is rapidly developing in response to energy shortage and environmental pollution. ABX 3 perovskite materials have gained widespread attention in photocatalysis due to their narrow band gap, high quantum efficiency, and high carrier mobility. The energy band structure plays a critical role in carrier generation, separation and redox processes in photocatalytic reactions. In this paper, we modulated the energy band structures of CsPbBr 3 and UiO-66 by changing the reaction parameters, and prepared CsPbBr 3 /UiO-66 composites with different energy band structures to investigate photocatalytic activities. Our results showed that the degradation rate of (Methyl Orange) MO by CsPbBr 3 /UiO-66 was significantly enhanced. The change in the CsPbBr 3 energy band structure did not significantly affect the photocatalytic activity of the composites. This work provides a new opportunity to improve the photocatalytic performance of perovskite-based composites using the energy band structure regulation strategy. Our findings may contribute to the design and development of highly efficient and stable perovskite-based photocatalysts for environmental remediation and energy conversion. The study focuses on ABX 3 perovskite materials, which have garnered significant attention in photocatalysis due to their advantageous characteristics, including a narrow band gap, high quantum efficiency, and excellent carrier mobility. The research explores the pivotal role of the energy band structure in processes such as carrier generation, separation, and redox reactions within photocatalytic systems. [Display omitted] • UiO-66 band gap reduction limits carrier separation and photocatalytic activity in CsPbBr3/UiO-66 composites. • Energy band structure regulation offers a way to enhance perovskite-based photocatalytic performance. • Findings aid in developing efficient, stable perovskite photocatalysts for environmental and energy applications. [ABSTRACT FROM AUTHOR]

Abstract In this paper, on the basis of first-principles, the CASTEP module of Materials Studio is used to calculate the band structures and optical properties of CuFeSe2 and CuFeS2 under the PBE pseudopotential of the generalized gradient approximation (GGA). The calculated results show that both CuFeSe2 and CuFeS2 are direct bandgap semiconductors with forbidden band widths of 0.64 eV and 1.06 eV, respectively. In the visible light range, the highest absorption coefficient of CuFeSe2 is 1.082×105 cm-1, the average reflectivity is 0.52, the maximum conductivity is 7.23 fs-1, the electrostatic constant is 65.9; the maximum value the highest absorption coefficient of CuFeS2 is 0.872×105 cm-1, the average reflectivity is 0.44, the maximum conductivity is 4.44 fs-1, the static dielectric constant is 52.32. The calculation results in this paper show that compared with CuFeS2, CuFeSe2 has advantages in photoconductivity and carrier separation, but has disadvantages in band gap and reflectivity. It is recommended to combine the two materials to prepare tandem solar cells.

In this paper, a coupled piezoelectric/semiconducting model is established and applied to study the effect of arbitrarily-located axial mechanical loadings on electric potential distribution in ZnO nanofiber, and the corresponding energy bands are computed via an eight-band k·p method. Results show that the band gap can be tuned by about 25 meV at band edges and about 200 meV away from band edges. The maximum valance band and minimum conduction band are located at band edges. The good mechano-electric effect of piezoelectric semiconductors and the simulating method presented in this paper can be used in designing novel semiconductor devices. [ABSTRACT FROM AUTHOR]

The scaffold layer plays an important role in transporting electrons and preventing carrier recombination in mesoporous perovskite solar cells (PSCs), so the engineering of the interface between the scaffold layer and the light absorption layer has attracted widespread concern. In this work, vertically grown TiO2 nanorods (NRs) as scaffold layers are fabricated and further treated with TiCl4 aqueous solution. It can be found that a thin brookite TiO2 nanoparticle (NP) layer is formed by the chemical bath deposition (CBD) method on the surface of every rutile NR with a low annealing temperature (150 °C), which is beneficial for the infiltration and growth of perovskite. The PSC based on the TiO2 NR/brookite NP structure shows the best power conversion of 15.2%, which is 56.37% higher than that of the PSC based on bare NRs (9.72%). This complex structure presents an improved pore filling fraction and better carrier transport capability with less trap-assisted carrier recombination. In addition, low-annealing-temperature-formed brookite NPs possess a more suitable edge potential for electrons to transport from the perovskite layer to the electron collection layer when compared with high-annealing-temperature-formed anatase NPs. The brookite phase TiO2 fabricated at a low temperature presents great potential for flexible PSCs. [ABSTRACT FROM AUTHOR]

Mechanoelectric energy conversion holds promise for energy conversion and transmission devices, yet conventional configurations rely on large-area conductive materials in active regions, limiting architectural design for cutting-edge devices. Here, a rational strategy is reported to create mechanical stimuli-driven pseudo-conductive (MSPC) channels entirely from dielectric materials, eliminating the need for electrodes in active regions. An in-depth investigation of MSPC channel formation mechanism at dielectric interfaces is conducted, employing energy band analyses. Following the mechanical stimuli-driven charging process, MSPC device effectively transmits electrical signals over 42 mm, achieving remarkable 512% enhancement compared to its pristine state. Control devices with non-continuous dielectric configurations highlight the impact of heterojunction interfaces on MSPC channels. A resistor-capacitor charging test reveals up to 49% reduction in voltage change rate, indicating a substantial decrease in electrical impedance along the MSPC channel. Furthermore, MSPC devices demonstrate information transmission capabilities, such as sequences of bits or letters, utilizing solely dielectric configurations. This study paves the way to reduce conductive materials of wearable electronics, biomedical implants, and IoT technologies, overcoming significant challenges such as potential electrical shortages, design inflexibility, limited manufacturing scalability, and maintenance issues., (© 2024 Wiley‐VCH GmbH.)

Antimony selenide (Sb 2 Se 3 ) has sparked significant interest in high-efficiency photovoltaic applications due to its advantageous material and optoelectronic properties. In recent years, there has been considerable development in this area. Nonetheless, defects and suboptimal [hk0] crystal orientation expressively limit further device efficiency enhancement. This study used Zinc (Zn) to adjust the interfacial energy band and strengthen carrier transport. For the first time, it is discovered that the diffusion of Zn in the cadmium sulfide (CdS) buffer layer can affect the crystalline orientation of the Sb 2 Se 3 thin films in the superstrate structure. The effect of Zn diffusion on the morphology of Sb 2 Se 3 thin films with Cd x Zn 1-x S buffer layer has been investigated in detail. Additionally, Zn doping promotes forming Sb 2 Se 3 thin films with the desired [hk1] orientation, resulting in denser and larger grain sizes which will eventually regulate the defect density. Finally, based on the energy band structure and high-quality Sb 2 Se 3 thin films, this study achieves a champion power conversion efficiency (PCE) of 8.76%, with a V OC of 458 mV, a J SC of 28.13 mA cm -2 , and an FF of 67.85%. Overall, this study explores the growth mechanism of Sb 2 Se 3 thin films, which can lead to further improvements in the efficiency of Sb 2 Se 3 solar cells., (© 2024 Wiley‐VCH GmbH.)

Surface modification and wetting state transformation of ZnO based nanomaterials have been extensively investigated due to their substantial roles in current industrial applications. In this work, we demonstrated the formation of highly crystalline and ordered Bi/ZnO nanorods arrays (Bi/ZNRs) grown on FTO substrate via a feasible hydrothermal method, as a function of reaction time (t). The lateral diameter of the nanostructures were found increased from 23 nm to 43 nm when the reaction time increased from 30 min to 90 min. An in-depth analysis and incisive mechanism of crystal growth under the function of reaction time were proposed. The crystal defect which originated from different Bi incorporation pathways has been declared as the main factor altering the optical energy, electrical properties and band structure of Bi/ZNRs. The Bi/ZNRs showed a higher localize current of 14.5 pA as compared to pristine ZNRs under an 6V applied bias condition, revealing the nature of Bi as a pentavalent dopant that contributed to a density of free electron. Additionally, the Bi/ZNRs also revealed a red shifted in optical energy band gap and exhibit a wetting transition from hydrophobic to hydrophilic textured surface. The novel nanostructures reported herein exhibit interesting physical and optical properties for the fabrication of high performance optoelectronic devices.

SiC/Si and GaN/Si heterojunction technology has been widely used in power semiconductor devices, and SiC/Si VDMOS and GaN/Si VDMOS were proposed in our previous paper. Based on existing research, breakdown point transfer technology (BPT) was used to optimize SiC/Si VDMOS. Simulation results showed that the BV of the SiC/Si heterojunction VDMOS was considerably increased from 259 V to 1144 V, and Ron,sp decreased from 18.2 mΩ·cm2 to 6.03 mΩ·cm2 compared with Si VDMOS. In order to analyze the characteristics of the SiC/Si heterojunction structure deeply, the influence of the interface state characteristics of the SiC/Si heterojunction on the electrical parameters of VDMOS was analyzed, including electric field characteristics, blocking characteristics, output characteristics, and transfer characteristics. In addition, the influence of the interface state of the SiC/Si heterojunction on energy band characteristics was analyzed. The results showed that with an increase in the interfacial charge (acceptor) concentration, the p-type trap layer was introduced into the interface of the SiC/Si heterojunction, energy increased slightly, and the barrier height difference at the heterojunction increased, resulting in an increase in BV. At the same time, since the barrier height became higher, electrons did not flow easily, so Ron,sp increased. On the contrary, when a charge (donor) was introduced at the interface of the SiC/Si heterojunction, the number of electrons in the channel increased, resulting in an increase in the electron current, which is conducive to the flow of electrons, resulting in a decrease in Ron,sp. The energy band and other characteristics of devices with temperature were simulated at different temperatures. Finally, the effects of SiC/Si heterojunction interface states on interface capacitances and switching performances of VDMOS devices were also discussed.

Metal oxide photocatalyst is a promising wastewater treatment process due to its simplicity, high efficiency, and low cost, as well as being environmentally friendly and non-energy consuming. The perovskite structure material, SrTi1−xNbxO3 (STNO) with x = 0, 0.01, 0.03, and 0.05, was successfully synthesized by the sol-gel auto-combustion method. Samples with a pure phase and cubic perovskite structure were obtained. The Rietveld refinement results showed that the lattice parameter and unit cell density increased as the Nb-doping level increased. The particle size of the STNO decreases with increasing Nb doping content. Photoluminescence was excited at 327 nm, producing violet, green, and blue emissions, while the Nb content asserts an insignificant effect on the bandgap (Eg). The Nyquist plot and Mott-Schottky analysis were used to determine the photoelectrode performance of the STNO samples. The photocatalytic activity of STNO on the decolorization of methylene blue (MB) under UV irradiation increased with increasing Nb content and optimization at x = 0.05, corresponding to the results obtained from photoluminescence, Eg, Nyquist plot, and Mott-Schottky analyses. [ABSTRACT FROM AUTHOR]

The energy band dependent mobility in heterojunction amorphous oxide semiconductor thin‐film transistors (TFTs) is investigated. Results indicate that both of the energy band configurations with potential well (PW) and barrier (PB) formation could allow TFT with high‐mobility operation. Specifically, TFT with PW only exhibits high mobility when the gate electric field direction is consistent with that of build‐in electric field in PW, whereas TFT with PB could exhibit high mobility no matter what the electric field direction configuration is. [ABSTRACT FROM AUTHOR]

Lead‐free Cs2AgBiBr6 double perovskite has received widespread attention because of its non‐toxicity and high thermal stability. However, intrinsic bromide ion (Br–) migration limits continuous operation of Cs2AgBiBr6‐based perovskite solar cells (PSCs). Herein, an operational and simple strategy is carried out to improve the power conversion efficiency (PCE) and long‐term stability of Cs2AgBiBr6‐based PSCs by introducing 1‐butyl‐1‐methylpyrrolidinium chloride (BMPyrCl) and 1‐butyl‐3‐methylpyridinium chloride (BMPyCl) ionic liquids (ILs). The higher binding energy between Br– in Cs2AgBiBr6 and cation in IL containing pyrrole can inhibit Br– migration effectively, thereby reducing film defects and improving energy level matching. The optimized PCE of 2.22% is obtained for hole transport layer‐free, carbon‐based PSC, which hardly degrades at 40% ± 5% relative humidity and 25 °C for 40 days. This work highlights an effective method to mitigate the halide migration in Cs2AgBiBr6 perovskite, thus providing an effective route in promoting the development of lead‐free double PSCs. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on density functional theory and Debye quasi-harmonic approximation, the effects of high pressure on the phonon, electronic, elastic, and thermodynamic properties of the orthogonal phase HfSi2 have been calculated. The calculated results show that when the pressure is within the pressure range of 0 GPa to 50 GPa, HfSi2 is dynamically stable, and there is no virtual frequency on the phonon spectrum, but when the pressure is greater than 70 GPa, virtual frequencies appear near the phonon spectrum X, A structural phase change occurred. We predict that the band structure of HfSi2 is metallic. As the pressure increases, the elastic constant Cij increases and conforms to the Born criterion. It is mechanically stable in a certain pressure range. At the same time, B, E, G, and B/G all increase with the increase of pressure. This shows that changing the pressure appropriately can change the ductility and toughness of the material. The Debye temperature and sound velocity increase linearly with the increase of pressure, so the elasticity, hardness, melting point, and specific heat of the material can be improved by pressure. [ABSTRACT FROM AUTHOR]

• Variuos hole-transport layers are used independently. • Ohmic contact region is identified by tuning electrode work functions. • Based on our results, an alternate to Au, low-cost contact materials are suggested. • Commonly used expensive hole-transport layer can be replaced. • Current density depends on reflectance from hole-transport layer. Metal halide perovskites are promising absorber materials for solar cell applications due to (i) low-cost processing methods, and (ii) cell efficiency is comparable to the standard silicon solar cells. Methylammonium lead bromide (CH 3 NH 3 PbBr 3) is a metal halide perovskite having wide band gap suitable for high open-circuit voltage (V oc) solar cell. Here we report the performance of CH 3 NH 3 PbBr 3 based solar cells by using various hole-transport layers (HTLs) independently with titanium dioxide (TiO 2) as electron transport layer (ETL). Spiro-OMeTAD was used as HTL in the control device. Absorbance study indicates the band gap of CH 3 NH 3 PbBr 3 is around 2.25 eV. Energy band alignment shows the superior band alignment across the device when copper thiocyanate (CuSCN) is used. Short-circuit current density (J sc) is independent of electrode work functions. However, J sc depends upon internal reflection at the absorber/HTL interface and reflection is high for CuSCN and low for nickel oxide (NiO). Our result shows that fill factor and efficiency depends on absorber thickness, top and bottom electrode work functions. For Ohmic contact, top electrode and bottom electrode work functions must be between −4.0 eV to −4.4 eV and −4.9 eV to −5.26 eV respectively and device performs excellent in these regimes. For the control device, V oc , J sc , fill factor, and efficiency of 2.10 V, 9.64 mA/cm2, 0.90, and 18.42% were obtained. Whereas for the cell having CuSCN as HTL, a high efficiency of 23.39% with V oc of 2.10 V, J sc of 13.04 mA/cm2, and fill factor of 0.85 were obtained. [ABSTRACT FROM AUTHOR]

Cost-effective and controllable synthesis of M0.25Ni0.15Cu0.25Co0.35Fe2O4 (M2+ = Mg2+, Mn2+, and Cd2+) ferrites via the sol–gel auto-combustion technique. The impact of divalent cations on the structural, dielectric, and optoelectrical properties of ferrites was examined by XRD, FTIR, Raman, LCR, UV–Vis, and two probe I-V measurement techniques. The crystallite size was 52.66 nm, and the minimum specific surface area was observed 5.1507 m2/g for Mg2+ doped NCCF ferrite. The FTIR and Raman analysis also confirmed the substitution of divalent cations (M2+ = Mg2+, Mn2+, and Cd2+) at their respective lattice sites. The maximum energy bandgap was 1.67 eV Mg2+-doped NCCF ferrite as compared to other divalent ion-doped ferrites. The dielectric loss decreased while the ac conductivity increased with increasing frequency, and the minimum values were observed for Mg2+-doped NCCF ferrite. The activation energy was observed maximum for Mg2+-doped NCCF ferrite (0.2234 eV). Due to incredible properties including small specific surface area, large energy band gap, high resistivity, and loss dielectric loss of Mg2+-doped NCCF ferrite have potential applications in different fields. [ABSTRACT FROM AUTHOR]

Abstract Ceria-based heterostructure composite (CHC) has become a new stream to develop advanced low-temperature (300–600 °C) solid oxide fuel cells (LTSOFCs) with excellent power outputs at 1000 mW cm−2 level. The state-of-the-art ceria–carbonate or ceria–semiconductor heterostructure composites have made the CHC systems significantly contribute to both fundamental and applied science researches of LTSOFCs; however, a deep scientific understanding to achieve excellent fuel cell performance and high superionic conduction is still missing, which may hinder its wide application and commercialization. This review aims to establish a new fundamental strategy for superionic conduction of the CHC materials and relevant LTSOFCs. This involves energy band and built-in-field assisting superionic conduction, highlighting coupling effect among the ionic transfer, band structure and alignment impact. Furthermore, theories of ceria–carbonate, e.g., space charge and multi-ion conduction, as well as new scientific understanding are discussed and presented for functional CHC materials.

It is, in fact, inevitable for steel to be covered with a layer of iron oxides and/or peroxides on its surface. However, knowledge of its existence and functionality for tribological behaviors is usually ignored. Herein, covalent-organic framework nanomaterials (CONs) composed of three well-screened acceptors and a donor through the imide linkage were fabricated to explore their lubrication performances. The results indicate that the energy-level matching between CONs and iron oxides or peroxides leads to the formation of a Z-scheme heterojunction structure at the rubbing interface. Also, the friction produces an internal electric field in the heterojunction, which drives the negative atomic/ionic species from the sliding interface to immigrate into the pore of CONs and resettle inside to engender the pinning effects, producing a fixed lubrication layer. Synchronously, it also attracts the free CONs in the base oil to form an easy-shear lubrication layer assembling onto the fixed one, producing a lubrication film with two layered configurations. Finally, the unique lubrication film, despite its thickness of a dozen nanometers, still exhibits impressive friction reduction and antiwear. This finding will inspire the technology to utilize the intrinsic surface nature of steel materials to exploit lubricant additives or modulate tribological behaviors.

A metal-free nanocarbon with an eggshell structure is synthesized from chitosan (CS) and natural spherical graphite (NSG) as a cathode electrocatalyst for clean zinc-air batteries and fuel cells. It is developed using CS-derived carbons as an eggshell, covering NSG cores. The synthesis involves the in situ growth of CS on NSG, followed by ammonia-assisted pyrolysis for carbonization. The resulting catalyst displays a curved structure and completely coated NSG, showing superior oxygen reduction reaction (ORR) performance. In 1 M NaOH, the ORR half-wave potential reached 0.93 V, surpassing the commercial Pt/C catalyst by 50 mV. Furthermore, a zinc-air battery featuring the catalyst achieves a peak power density of 167 mW cm -2 with excellent stability, outperforming the Pt/C. The improved performance of the eggshell carbons can be attributed to the distorted energy band of the active sites in the form of N-C moieties. More importantly, the curved thin eggshells induce built-in electric fields that can promote electron redistribution to generate atomic charge waves around the N-C moieties on the carbon shells. As a result, the high positively charged and stable C + sites adjacent to N atoms optimize the adsorption strength of oxygen molecules, thereby facilitating performance., (© 2024 Wiley‐VCH GmbH.)

In this study, we design and simulate a metal implanted dielectrically modulated tunneling field-effect transistor (MI-DMTFET). In the ambipolar conduction state, the proposed structure works as an efficient sensor for the detection of a wide range of biomolecules. A metal strip (MS) is implanted above the drain-channel junction in the gate dielectric to improve the alignment of band gaps. Therefore, with the help of implanted metal work function engineering, the tunneling barrier gets lowered, which in turn increases the ambipolar current. An optimum metal-strip implant work function of 4.85 eV and a length of 1.5 nm have resulted in significantly improved performance of the proposed device. It has been observed that when the biomolecules with varying dielectric constants and charge densities are captured in the nanogap cavity, the ambipolar current of the biosensor changes, resulting in the detection of the biomolecules. Quantitative and comprehensive analyses of device parameters such as surface potential, electric field, band-to-band tunneling, subthreshold slope, and I ON / I OFF ratio analysis have been performed. Rigorous comparative analyses of key performance-measuring parameters have been performed with a conventional sensor device. It has been found that the proposed device offers maximum sensitivity of 1220 under an ambipolar state at k = 12.

This paper mainly studies the vibration isolation of negative Poisson's ratio structure in the honeycomb base of ships. Based on the structure of the negative Poisson's ratio structure, different laying methods and different cell structure are used to construct the honeycomb base with the re-entrant hexagonal cell, the mathematical expression of Poisson's ratio of a single re-entrant hexagonal cell structure is obtained through theoretical analysis. The negative Poisson ratio and relative density could be got by changing the angle and side thickness of the cell structure. Based on the different energy band of the re-entrant hexagonal cell structure, the different negative Poisson's ratio re-entrant hexagonal honeycomb base was got, the energy band and the frequency response curve of the ship base are analyzed by COMSOL software. The energy band diagram and the frequency response of the structure are obtained to analyze the vibration isolation performance of the honeycomb base. By comparing the experimental results, the following conclusions can be gotten: (1) Compared with the traditional base, the negative Poisson's ratio base has better vibration isolation effect on external excitation; (2) Different laying method and Poisson ratios can get different isolation effect. The combined base structure can provide better isolation effect to the external excitation in a larger frequency band; (3) By adding different mass blocks to the inner or peripheral angles of the basic re-entrant hexagonal cell, the vibration isolation performance of the structure can be changed to better. [ABSTRACT FROM AUTHOR]

The energy band of a novel Si0.7Ge0.3 source tunneling field-effect transistor (TFET) is successfully adjusted and sharply bent without any physical formation of metallurgical junction around the source/channel regions. By work function engineering, charge plasma of the hole is created inside the heavily doped n-type source region to convert the device from n-i-n to p-n-i-n. Hence, the reliability of the proposed device will increase during the thermal proceeding of the device. The reduced source bandgap and the electrical creation of metallurgical junction are stated as the principal factors intensifying the band-to-band tunneling (BTBT) rate, thereby increasing the drain current considerably. One of the substantial benefits is the neglectable variation of the leakage current for the proposed device promising a high ON– OFF current ratio. Comparing the proposed structure by the conventional TFET and the p-n-p-n TFET performed based on the simulation results revealed the electrical performance improvement. The significant parameters in terms of ON-current (${I}_{ \mathrm{\scriptscriptstyle ON}}{)}$ , transconductance (${g}_{\text {m}}{)}$ , output conductance (${g}_{\text {d}}{)}$ , voltage gain (${g}_{\text {m}}/{g}_{\text {d}}{)}$ , ${I}_{ \mathrm{\scriptscriptstyle ON}}/{I}_{ \mathrm{\scriptscriptstyle OFF}}$ , and trap-assisted tunneling (TAT) component have been successfully improved for the proposed device in comparison with the devices under study in this work. Hence, the suggested device is introduced as a reliable high-performance structure applicable in analog and digital applications. [ABSTRACT FROM AUTHOR]

The scaffold layer plays an important role in transporting electrons and preventing carrier recombination in mesoporous perovskite solar cells (PSCs), so the engineering of the interface between the scaffold layer and the light absorption layer has attracted widespread concern. In this work, vertically grown TiO2 nanorods (NRs) as scaffold layers are fabricated and further treated with TiCl4 aqueous solution. It can be found that a thin brookite TiO2 nanoparticle (NP) layer is formed by the chemical bath deposition (CBD) method on the surface of every rutile NR with a low annealing temperature (150 °C), which is beneficial for the infiltration and growth of perovskite. The PSC based on the TiO2 NR/brookite NP structure shows the best power conversion of 15.2%, which is 56.37% higher than that of the PSC based on bare NRs (9.72%). This complex structure presents an improved pore filling fraction and better carrier transport capability with less trap-assisted carrier recombination. In addition, low-annealing-temperature-formed brookite NPs possess a more suitable edge potential for electrons to transport from the perovskite layer to the electron collection layer when compared with high-annealing-temperature-formed anatase NPs. The brookite phase TiO2 fabricated at a low temperature presents great potential for flexible PSCs.

Copyright of Journal of Shenzhen University Science & Engineering is the property of Editorial Department of Journal of Shenzhen University Science & Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recent success in strain engineering has triggered tremendous interest in its study and potential applications in nanodevice design. In this paper, we establish a coupled piezoelectric/semiconducting model for a wurtzite structure ZnO nanofiber under the local mechanical loading. The energy band structure tuned by the local mechanical loading and local length is calculated via an eight-band k · p method, which includes the coupling of valance and conduction bands. Poisson's effect on the distribution of electric potential inversely depends on the local mechanical loading. Numerical results reveal that both the applied local mechanical loading and the local length exhibit obvious tuning effects on the electric potential and energy band. The band gap at band edges varies linearly with the applied loading. Changing the local length shifts the energy band which is far away from the band edges. This study will be useful in the electronic and optical enhancement of semiconductor devices. [ABSTRACT FROM AUTHOR]

Type VIII single crystal clathrates exhibit good characteristics of electron crystal-phonon glass because the special crystal structure. And the thermoelectric performance could be further improved be elemental doping, which could bring obvious improvement for the energy band structure and density of states. However, the mechanism here is not very clear. In this paper, we use first principles to calculate the lattice constant, band structure, density of states, etc. of type VIII Sn-based clathrates. These clathrates are set in form of original structure or structures doped with In, Zn, Cu and other elements. Studies have shown that the In, Zn and Cu doping increases the bulk modulus of the material, and reduces its band gap. Moreover, the In, Zn, Cu doping introduces impurity energy level, and changes the material frame of the atomic electron distribution. The thermoelectric properties of materials are optimized by doping different elements, due to different electronic distribution in the s, p, d layers, resulting in different influence on material band structure. [ABSTRACT FROM AUTHOR]

Type VIII single crystal clathrates exhibit good characteristics of electron crystal-phonon glass because the special crystal structure. And the thermoelectric performance could be further improved be elemental doping, which could bring obvious improvement for the energy band structure and density of states. However, the mechanism here is not very clear. In this paper, we use first principles to calculate the lattice constant, band structure, density of states, etc. of type VIII Sn-based clathrates. These clathrates are set in form of original structure or structures doped with In, Zn, Cu and other elements. Studies have shown that the In, Zn and Cu doping increases the bulk modulus of the material, and reduces its band gap. Moreover, the In, Zn, Cu doping introduces impurity energy level, and changes the material frame of the atomic electron distribution. The thermoelectric properties of materials are optimized by doping different elements, due to different electronic distribution in the s, p, d layers, resulting in different influence on material band structure. [ABSTRACT FROM AUTHOR]

Rolled-up quantum well (QW) nanomembranes with different diameters are prepared using the lift-off method. The structural evolution and the influences of voltage and temperature on the photoelectric properties of the nanomembranes are investigated. We find that a QW in tensile status can enhance the photorepsonse by about 2.1 times, and a QW in compressive status leads to a decrease of photorepsonse to ~ 65%. With increasing temperature, the gap between the ground state and excited state in the conduction band decreases with a rate of ~ 0.008 meV/K and the thermal effect mainly affects the shift of conduction band. For a working rolled-up device, the change of band gap due to the thermal effect from the applied voltage is negligible. [ABSTRACT FROM AUTHOR]