Search

We have developed a novel dressed-photon-assisted annealing process, in which the distribution of dopant (boron) domains is modified in a self-organized manner based on the absorption of light having a photon energy higher than the band gap and subsequent stimulated emission. Using this process, we were able to fabricate a bulk silicon p-n homojunction-structured light-emitting diode that showed electroluminescence emission in the visible region at room temperature. A broadband spectrum with three emission peaks at 400 nm, 590 nm, and 620 nm was clearly observed. [ABSTRACT FROM AUTHOR]

We investigated the coupling strength between electron-hole pairs and phonons in a silicon light emitting diode (Si-LED) fabricated by dressed-photon-assisted annealing. This Si-LED emitted light in the 1.4 eV photon energy (0.9 μm wavelength) band, and phonon sidebands were observed in the emission spectrum. From a comparison with simulation results, these sidebands were found to be due to coupling of electron-hole pairs with LO-mode and TO-mode coherent phonons via dressed-photon-phonons. The value of the Huang-Rhys factor, $S$, representing the coupling strength between the electron-hole pairs and the phonons was estimated to be $4.08 \pm 0.02$. [ABSTRACT FROM AUTHOR]

The potential usage of thermally robust RuOx Schottky contacts in III-nitride-based Schottky diodes and high electron mobility transistors (HEMTs) has been investigated. RuOx is deposited on nitride surface by sputtering Ru in Ar/O2 ambient. The influence of post sputtering annealing ambient and temperature on the characteristics of RuOx Schottky diodes on n-type GaN on Si(111) substrate is addressed. We also report the comparative study of thermal stability between RuOx and Ni/Au Schottky diodes on InxAl1-xN/GaN on Si(111) substrate in terms of the reverse bias leakage current and Schottky barrier height (SBH). RuOx contact shows a higher SBH of 1.24 eV and a lower leakage current of ∼10-5 Acm-2 (∼four orders of magnitude lower than that of Ni/Au) on InxAl1-xN/GaN at -40 V after annealing at 800 oC in N2. In addition, RuOx Schottky gate HEMT on InxAl1-xN/GaN on Si(111) substrate has shown a low gate leakage current of ∼6×10-8 A/mm at -8 V after annealing at 700 oC in N2 for 1 minute. The lower gate leakage current has resulted in a transistor ON/OFF current ratio of ∼105. The maximum transconductance and ON-resistance achieved by such HEMTs are about 0.18 S/mm and 8.33 Ωmm, respectively, for a gate length of 1.5 µm. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

This paper demonstrates the fabrication of self-aligned gate-last enhancement- and depletion-mode (E/D-mode) AlN/GaN metal-oxide-semiconductor high-electron-mobility-transistors (MOSHEMTs). In addition, the effects of annealing on threshold voltage ( Vth) are analyzed. The E and D-mode transistors were fabricated with Ni/Au and Ti/Au as the gate metal, respectively. The Ni/Au gated MOSHEMTs show Vth = +0.3 V after post-gate metallization annealing, and the Ti/Au gated MOSHEMTs without annealing show Vth= -1.8 V. In the E-mode (Ni/Au gated) transistors, the Vth shift after post-gate annealing is due to the decrease of fixed charges at the Al2O3/GaN interface. An investigation has been conducted for the understanding of the Vth shift, which is crucial for improving the transistors' stability in various applications. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The fabrication-procedure dependence of the electrical properties of the InAlN metal-oxide-semiconductor (MOS) structure with Al2O3 formed by atomic layer deposition (ALD) was investigated. When the ALD Al2O3/InAlN interface was formed after ohmic-contact annealing in nitrogen without the use of a cap layer, the electrical characteristics were poor with a small capacitance change in the capacitance-voltage (C-V) curve. X-ray photoelectron spectroscopy (XPS) study indicated that the bare InAlN surface was oxidized during capless annealing presumably owing to the trace contamination in the furnace. High-temperature ohmic-contact annealing after Al2O3/InAlN interface formation, using the Al2O3 layer as a cap layer for surface protection, did not improve the interface properties, resulting in the interface state density Dit in the range of 1013 cm-2eV-1; this was highly likely related to the crystallization of Al2O3. When a SiNx layer was used as the cap layer during ohmic-contact annealing prior to ALD, greatly improved characteristics of the MOS diode were achieved, indicating that Dit was suppressed to be in the range of 1012 cm-2eV-1 near the conduction band. The obtained results indicate that an appropriate fabrication procedure leads to an improvement of the Al2O3/InAlN interface properties. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The magnetic, dielectric, and magnetoelectric properties are investigated in the polycrystalline Cr2WO6. Under zero magnetic fields, no dielectric anomaly and electric polarization are observed in this compound. After magnetoelectric annealing, the magnetic-field-induced dielectric and pyroelectric current peaks simultaneously present around its Neel temperature and increase with increasing magnetic field, showing large magneto-dielectric and linear magnetoelectric effects in Cr2WO6. The origin of magnetoelectric effect in this compound is discussed. [ABSTRACT FROM AUTHOR]

Ion beam assisted deposition (IBAD) is a promising technique for improving the material quality of ZnO-based thin films. The operation of an auxiliary Ar+ ion source during deposition of ZnO : Ga thin films by dc magnetron sputtering led to an improvement in crystalline texture, especially at low temperatures due to momentum transfer from the ions to the growing film. Etching of IBAD-ZnO : Ga films in diluted HCl revealed crater-like surface structures with crater diameters of up to 600 nm. These structures are usually achieved after deposition at high substrate temperatures. This is an indication that the grain structure was remarkably changed by bombarding these films during deposition in terms of increasing the compactness of the ZnO : Ga films. Subsequent annealing procedures led to an improvement in the electrical and optical properties. Hydrogenated microcrystalline silicon (µc-Si : H) solar cells exhibited enhanced efficiency as compared to cells on other low-temperature sputtered reference ZnO films. This improvement was ascribed to light trapping by the modified etching behaviour of the IBAD-ZnO : Ga films as well as improved transparency after the vacuum annealing step. [ABSTRACT FROM AUTHOR]

Upconversion in radio frequency magnetron sputtered Er-doped zinc oxide thin films on Si substrate has been demonstrated using 1550 nm cw laser excitation. As-sputtered thin films did not show any upconversion emission, and annealing was required to optically activate the Er3+-ions. Emissions at 985, 809, and 665-675 nm were observed in annealed thin films, corresponding to transitions from 4I11/2, 4I9/2, and 4F9/2 to the ground state 4I15/2, respectively. The emission from 4I11/2 was the dominant one, whereas emission from 4I9/2 was the weakest. The highest intensity at 985 nm was obtained with 2.4 at.% of Er by annealing the film at 700 ℃. Annealing at higher temperatures causes Er to diffuse and segregate to the Si-ZnO interface between the Si substrate and the ZnO film. [ABSTRACT FROM AUTHOR]

We demonstrate self-aligned Ni-GaSb alloy source/drain (S/D) junctions for GaSb p-channel metal-oxide-semiconductor field-effect transistors (p-MOSFETs). Ni-GaSb alloys are used as self-aligned S/D junctions for GaSb p-MOSFETs formed with low-temperature annealing at 250 °C. Low-temperature process is preferred to avoid temperature-induced problems, because GaSb MOS gate stacks can show better MOS interface properties with lowering process temperature. This low-temperature S/D formation allowed us to realize the normal transistor operation of GaSb p-MOSFETs. Ni-GaSb alloy junctions can show the low contact resistivity with shallow junction depth. Self-aligned Ni-GaSb alloy S/D junctions can be an appropriate S/D junction technology for GaSb p-MOSFETs. [ABSTRACT FROM AUTHOR]

Creating uniform coatings of a solution-cast material is of central importance to a broad range of applications. Here, a robust and generic theoretical framework for calculating surface coverage by a solid film of material de-wetting a substrate is presented. Using experimental data from semiconductor thin films as an example, we calculate surface coverage for a wide range of annealing temperatures and film thicknesses. The model generally predicts that for each value of the annealing temperature there is a range of film thicknesses leading to poor surface coverage. The model accurately reproduces solution-cast thin film coverage for organometal halide perovskites, key modern photovoltaic materials, and identifies processing windows for both high and low levels of surface coverage. [ABSTRACT FROM AUTHOR]

Microwave annealing (MWA) and rapid thermal annealing (RTA) of dopants in implanted Si are compared in their abilities to produce very shallow and highly activated junctions. First, arsenic (As), phosphorus (P), and BF2 implants in Si substrate were annealed by MWA at temperatures below 550^\circC. Next, enhancing the substitutional carbon concentration ([C]sub) by cluster carbon implantation in (100) Si substrates with MWA or RTA techniques was investigated. Annealing temperatures and time effects were studied. Different formation mechanisms of SiCx layer were observed. In addition, substrate temperature is an important factor for dopant activation during MWA and in situ doped a-Si on oxide/Si substrate or glass were compared to elucidate the substrate temperature effect. After the discussion of dopant activation in Si substrates, low temperature formation of ultrathin NiGe layer is presented. Ultrathin NiGe films with low sheet resistance have been demonstrated with a novel two-step MWA process. In the two-step MWA process, the first step anneals the sample with low power MWA, and the second step applies higher power MWA for reducing sheet resistance. During fixed-frequency microwave heating, standing wave patterns may be present in the MWA chamber resulting in nodes and antinodes and thermal variations over the process wafer. Therefore, the effects of Si or quartz susceptor wafers on dopant activation and sheet resistance uniformity during fixed-frequency MWA were investigated. [ABSTRACT FROM PUBLISHER]

This paper analyzes both experimentally and by simulation the impact of traps on the transfer characteristics of tunnel-FETs (TFETs). The interface trap density in vertical heterojunction TFETs is varied by annealing in hydrogen or deuterium ambient. We show that a high-interface trap density (\sim 2\times 10^12/cm^2) results in a peak current in the device transfer characteristic at low-gate bias due to surface generation of carriers. The passivation of interface traps to state-of-the-art densities near 1-2\times 10^11/cm^2 reduces this peak, but improves only marginally the overall subthreshold swing, indicating that the trap-assisted tunneling responsible for the swing degradation is mainly occurring through bulk traps in these devices. [ABSTRACT FROM PUBLISHER]

The impacts of 3-D integration processes on memory retention characteristics in thinned DRAM chip were evaluated. The retention characteristics of DRAM cell in a DRAM chip which was face-down bonded to an interposer with under-fill degraded depending on the decreased chip thickness, especially dramatically degraded below 40-\mum thickness. Meanwhile, the retention characteristics of DRAM cell in a DRAM chip which was bonded without under-fill relatively not so degraded until to 30-\mum thickness, but suddenly degraded below 20-\mum thickness. The retention characteristics of DRAM cell in the thinned DRAM chip which was CMP-treated dramatically degraded after intentional Cu diffusion from the backside surface at 300^\circC annealing, regardless of the well structure. Meanwhile, the retention characteristics of DRAM cell in the thinned DRAM chip which was DP-treated not degraded even after Cu diffusion at 300^\circC annealing. [ABSTRACT FROM PUBLISHER]

The present work reports on the resistivity of anodic TiO2 nanotubes as function of annealing temperature and atmosphere. Significant effects of several orders of magnitude are observed and explained by different crystallinity and self-doping level. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Double-filled skutterudites InPrCoSb, which are currently being investigated for potential applications as thermoelectric materials, have been successfully prepared by inductive melting and annealing. Our results showed that In and Pr double filling effectively improves both electrical conductivity and Seebeck coefficient compared with pristine or single-filled CoSb, giving rise to a respectable power factor. The largest power factor, 2.33 m Wm K, was achieved at 609 K for InPrCoSb; this value is approximately three times that for InCoSb ( x ≤ 0.3) skutterudites. These results imply that In and Pr double filling are better than In single filling for efficient improvement of the thermoelectric properties of CoSb skutterudite. [ABSTRACT FROM AUTHOR]

Rapid thermal annealing in a belt furnace results in a dramatic change of the recombination properties of boron-doped Czochralski silicon: (1) the lifetime degraded by applying a prolonged illumination at room temperature was significantly improved, (2) after subsequent dark recovery, the lifetime has a remarkably high value, and (3) the permanent recovery, by annealing at 185°C under illumination, is enormously accelerated, and the finally achieved stable lifetime acquires a record value of 1.5 ms, as compared to 110 μs after permanent recovery of not-annealed reference samples [ABSTRACT FROM AUTHOR]

We develop a strategy to investigate bridge role of O-related defects in the neighbor of Eu3+ in energy transfer (ET). By solvothermal reactions and following annealing process, Eu3+ doped ZnO nanocrystal is synthesized. After low-temperature annealing, Eu3+ ions occupy substituted sites of ZnO. High temperature annealing results in self-purification process—the separation of Eu3+ ions from ZnO lattice and generation of Eu2O3 precipitate phases. However, in this case, the proportion of individual Eu2O3 particles is extremely low if they are separated. The precipitate phases have paralleled edges and parallel to (01̄1̄1) plane of ZnO. By self-purification separation, these O-terminated planes are easy to couple with Eu3+ ions, and form Eu3+ trap state. In order to maintain hexa-coordinate of Eu3+ ions, many O-related vacancies and interstitial defects are generated in the interface of ZnO/Eu2O3, among which interstitial O (Oi) in the neighbor of Eu3+ ions plays an important role in balance charge and ET. Thus, it is not strange to observe enhanced luminescence peak in self-purified samples. [ABSTRACT FROM AUTHOR]

Quantum information technologies require networks of interacting defect bits. Color centers, especially the nitrogen vacancy (NV–) center in diamond, represent one promising avenue, toward the realisation of such devices. The most successful technique for creating NV– in diamond is ion implantation followed by annealing. Previous experiments have shown that shallow nitrogen implantation (<10 keV) results in NV– centers with a yield of 0.01%–0.1%. We investigate the influence of channeling effects during shallow implantation and statistical diffusion of vacancies using molecular dynamics and Monte Carlo simulation techniques. Energy barriers for the diffusion process were calculated using density functional theory. Our simulations show that 25% of the implanted nitrogens form a NV center, which is in good agreement with our experimental findings. [ABSTRACT FROM AUTHOR]

In this study, the microstructures and superconducting properties of Bi, Pb-2223 thin films on SrTiO3(100) fabricated by radio-frequency (RF) sputtering and annealing have been investigated. Most of the as-deposited films fabricated by RF sputtering did not exhibit a superconducting transition, due to low crystallinity, deviation from the composition of Bi-2223, and low intergrain connectivity. The as-deposited films did not contain Pb. To obtain the Bi, Pb-2223 phase, we annealed the film with Bi, Pb-2223 pellets and powder. After annealing, we confirmed that the thin film contained Pb. A zero-resistance transition temperature of 100 K was obtained in the Bi, Pb-2223 thin film after post-annealing. We observed strong 00l peaks and a sharp quadrupole in x-ray θ–2θ and ϕ-scan measurements. These results suggested that this film consists of a single phase of Bi, Pb-2223 and has a biaxial orientation. The Bi, Pb-2223 thin film had a maximum critical current density of 0.9 × 105 A cm−2 at 77 K in a self-field. Furthermore, Bi, Pb-2223 exhibited very strong anisotropy in its critical current density–magnetic field angle characteristics. [ABSTRACT FROM AUTHOR]

The stability and the evolution of electrical properties of high concentration arsenic ultra-shallow junctions in silicon have been studied with regard to their effect on the evolution of point defects. The activation of 2 keV 1 × 1015 cm-2 As implants was performed using millisecond sub-melt laser annealing at two different temperatures, 1100 and 1300 °C. The electrical deactivation upon subsequent thermal treatment at 700 °C was indirectly monitored through the diffusion of five 10 nm-wide boron layers aimed to detect the injection of self-interstitials coming from dopant clustering. Thermal treatments were repeated on samples implanted with Ge at condition similar to the As ones. The comparison helped to discriminate between interstitials coming from lattice damage evolution and dopant clustering. The results show the relevance of the laser annealing temperature in order to ensure junction stability in terms of active carrier concentration and junction depth. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

We demonstrate a facile annealing method to improve the polymer chain ordering of poly(3-hexythiophene) (P3HT):fullerene blend triggered by a small amount of FePt nanowires (FePt NWs). By applying a magnetic field perpendicular to the substrate during the solvent drying process, the resulting P3HT:fullerene:FePt NWs film becomes highly optical anisotropy and exhibits a much stronger X-ray diffraction intensity of P3HT. We hypothesize that the coupling force between the FePt NWs and P3HT can assist the polymer chain alignment leading to an improved device performance. The proposed approach is simple and can be applied to other polymer blend systems as well. [ABSTRACT FROM AUTHOR]

Self-interference correlation imaging is a recently discovered method that takes advantage of holographic reconstruction when using a spatially incoherent light. Although the temporal coherence of light significantly influences the resolution of the method, it has not been studied either theoretically or experimentally. We present the first systematic study of the resolution in a broadband correlation imaging based on the concept of coherence-induced diffraction. We show that the physical limits of the resolution are reached in a non-dispersive experiment and their examination can be performed by the coherence aperture whose width depends on the coherence length of light and the optical path difference of interfering waves. As the main result, the optimal configuration of the non-dispersive experimental system is found in which the sub-diffraction image resolution previously demonstrated for monochromatic light can be retained even when the white light is used. Dispersion effects that prevent reaching the physical resolution limits are discussed and the dispersion sensitivity of the currently available experiments examined. The proposed concept of the coherence aperture is verified experimentally and its generalization to the concept of the dispersion-induced aperture suggested. As a challenge for future research, possible methods of dispersion elimination are outlined that allow the design of advanced optical systems enabling implementation of the high-resolution white light correlation imaging. [ABSTRACT FROM AUTHOR]

Magnesium silicide (Mg2Si) is an attractive semiconductor material for application to thermo-electric conversion devices because it consists of non-toxic and resource-abundant elements. There were difficulties, however, in preparation of Mg2Si thin films coming from large difference in thermodynamic properties between Mg and Si. In the present study, preparation of Mg2Si thin films by solid-phase synthesis; thermal annealing of metallic Mg on a Si substrate in argon gas atmosphere, is tested and optimum annealing conditions for the synthesis are explored. As a result, it is found that the optimum annealing temperature is 300-350 °C and the argon gas pressure should be higher than 50 Pa. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Structure and properties of spherical silicon solar cells with anti-reflection thin films were investigated and discussed. Conversion efficiencies of spherical Si solar cells coated with F-doped SnO2 anti-reflection films were improved by annealing. Optical absorption and fluorescence of the solar cells increased after annealing. Lattice constants of F-doped SnO2 anti-reflection layers, which were investigated by X-ray diffraction, decreased after annealing. Mechanisms of atomic diffusion in SnO2 and reactions at the Si/metal interface were discussed. The present work indicated a guideline for spherical silicon solar cells with higher efficiencies. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Nanoparticles of the spinel ferrite Mn0·7Zn0·3Fe2O4, with potential for use as contrast agents for magnetic resonance imaging applications, have been prepared by a sol-gel method followed by a two stage annealing process. The second stage of the annealing process improved the quality of the nanoparticles but also led to intergrown aggregates. The nanoparticles were milled to reduce this aggregation. After hand milling, the average nanoparticle size was 20 nm and after 5 h ball milling, the average nanoparticle size was 10 nm. The principal objectives of this study were to assess the effects of the two stage annealing process and milling on average nanoparticle size, crystal quality and magnetic properties relating to potential use in magnetic resonance imaging. Preliminary cytotoxicity measurements enabled assessment of possible nanoparticle contamination during milling on potential medical and clinical applications. A special surfactant was modified to disperse the nanoparticles in water and render them hydrophilic and to reduce agglomeration. [ABSTRACT FROM AUTHOR]

High-mobility and highly reliable self-aligned top-gate oxide thin-film transistor (TFTs) were developed using the aluminum reaction method. Al diffusion to the oxide semiconductor and homogenization of the oxygen concentration in the depth direction after annealing were confirmed by laser-assisted atom probe tomography. The high mobility of the top-gate TFT with amorphous indium tin zinc oxide channel was demonstrated to be 32 cm2/V s. A 9.9-in. diagonal qHD active-matrix organic light-emitting diode (AM-OLED) display was fabricated using a five-mask backplane process to demonstrate an applicable solution for large-sized and high-resolution AM-OLEDs. [ABSTRACT FROM AUTHOR]

We report hybrid vertical architecture p-type transistors with poly(N-vinylcarbazole) as the emitter, p-type silicon as the collector and Al:Ca alloy layer as the base. The investigation of the common-base and common-emitter characteristics clearly demonstrates that the devices operate as permeable-base transistors (PBTs). The PBTs show common-base current gain α of 0.98 at −VBC = 1.5 V and common-emitter gain β of over 100. Atomic force microscope images of the base layer show an uneven surface, showing that the annealing does not dissolve the charge trap states but offers ‘pinholes’ for the oxidation in-depth even through the whole base layer. In this case, the charge carriers must tunnel the thin oxidized layer, and then are collected. It is clearly seen that there exists a barrier against holes injection from the base to the collector semiconductor at the interface, and the further oxidation caused by exposing the devices in air changes the operational mode of the resulting devices from the PBT to the metal-base transistor. [ABSTRACT FROM AUTHOR]

We report that the transport critical current density Jc of ex situ powder-in-tube (PIT) processed (Ba, K)Fe2As2 (Ba-122) tapes can be significantly enhanced by applying uniaxial cold pressing at the final stage of deformation. The tapes were prepared by packing high quality precursor powder into a Ag tube, cycles of rolling and intermediate annealing, and pressing followed by the final heat treatment for sintering. The Jc values in applied magnetic fields were increased by almost one order of magnitude compared to the tapes processed without pressing, exceeding 104 A cm−2 at 4.2 K. We achieved the highest Jc (at 4.2 K and 10 T) of 2.1×104 A cm−2 among PIT-processed Fe-based wires and tapes reported so far. The Jc–H curves measured at higher temperatures maintain small field dependence up to around 20 K, suggesting that these tapes are promising for applications at higher temperatures as well as at liquid helium temperature. The microstructure investigations reveal that there are two possible causes of the large Jc enhancement by pressing: one is densification and the other is the change of crack structure. Optimization of processing parameters such as the reduction ratio of rolling and pressing is expected to yield further Jc enhancement. [ABSTRACT FROM AUTHOR]

Hf-based dielectrics were prepared using atomic layer deposition in order to investigate the effect of Si incorporation on the interfacial reaction and thermal stability in HfO2 films on SiGe substrates. Two concentrations [100% HfO2 and 50% HfO2 50% SiO2(HfSiO)] were used on strained Si0.7Ge0.3 substrates; a partially-crystalline phase was observed in the as-grown HfO2 film, and was not observed in the as-grown HfSiO film. Phase separation between the SiO x and HfO x in HfSiO film did occur, however, when the annealing temperature was increased to over 900 °C, leading to the out-diffusion of Si from the Si0.7Ge0.3 substrate and the formation of a Ge-rich layer at the interface between HfSiO and Si0.7Ge0.3. Finally, the strain in the Si0.7Ge0.3 substrate was relaxed, and interfacial states greatly increased in HfSiO/Si0.7Ge0.3 with the 900 °C anneal. [ABSTRACT FROM AUTHOR]

We propose and demonstrate an extremely efficient annealing for the RuO2 · xH20 nanoparticles incorporated in a supercapacitor employing intensely pulsed white light (IPWL). The IPWL process ensures the significant advantage of a room-temperature and millisecond-scaled process under ambient conditions. Resultant nanomorphology and crystallinity of Ru02 · xH20 electrodes are analyzed for process optimization. Electrochemical characteristics of the IPWL-treated electrodes were investigated by cycle voltammetry, resulting in a specific capacitance of 439 F/g at 10 mV/s with the irradiated IPWL energy of 2.04 J/cm² in 23 msec. [ABSTRACT FROM AUTHOR]

Effects of postannealing on Ti/Au-MgZnO contact and n-MgZnO/p-Si heterojunction ultraviolet-B photodetector's performance are investigated. It is found that the out diffusion of oxygen from MgZnO and its bonding with Ti at the interface have significant influences on the properties of Ti/MgZnO interface and photodetector. The persistent photocurrent observed in the annealed device is attributed to the oxygen vacancies near the interface, consistent with the theoretical calculations. It is revealed that the reaction at metal/MgZnO interface possibly plays a key role and even dominates the MgZnO p-n heterojunction ultraviolet detectors' performances. [ABSTRACT FROM AUTHOR]

Electrical evaluation along with the material analysis and reliability investigation of cosputtered Cu/Ti bonded interconnect in 3-D integration is presented in this paper. Diffusion behavior of cosputtered metals under different bonding ambient is evaluated as well. This paper shows that the bonded structure exhibits several interesting features under atmospheric bonding ambient, including self-formed adhesion layer, Cu–Cu bonding, and Ti oxide sidewall passivation. Electrical and reliability investigations of cosputtered Cu/Ti bonded interconnects show an excellent electrical performance and a high stability under a large variety of reliability tests, indicating the potential of using cosputtered Cu/Ti bonded interconnects for 3-D integration applications. [ABSTRACT FROM AUTHOR]

The extreme sensitivity of Sm/Ba at high temperature in air becomes an obstacle to the fabrication of SmBCO single grains that exhibit stable and reliable superconducting properties. In this research, the superconducting properties of SmBCO single grains fabricated by top seeded melt growth (TSMG) from different batches of commercial SmBa2Cu3O7-d (Sm-123) precursor powder using different processing atmospheres (air and 0.1% O2 in Ar), different processing methods (isothermal growth and continuous cooling) and different amounts of BaO2 content to suppress Sm/Ba substitution in air have been investigated in an attempt to understand fully the TSMG process for this system. As a result, based on extensive data, a novel and simple, low temperature post-annealing approach is proposed specifically to overcome the sensitivity of Tc to Sm/Ba substitution in order to simplify the fabrication of SmBCO and to increase its reliability with a view to the practical processing of these materials. Initial processing trials have been performed successfully to demonstrate the viability of the novel post-annealing process. [ABSTRACT FROM AUTHOR]

Electron microscopy studies of GaAs-based structures grown by molecular beam epitaxy and containing arrays of semiconductor InAs quantum dots and metal As quantum dots are performed. The array of InAs quantum dots is formed by the Stranski-Krastanov mechanism and consists of vertically coupled pairs of quantum dots separated by a GaAs spacer 10 nm thick. To separate the arrays of semiconductor and metal quantum dots and to prevent diffusion-induced mixing, the array of InAs quantum dots is overgrown with an AlAs barrier layer 5 or 10 nm thick, after which a GaAs layer is grown at a comparatively low temperature (180°C). The array of As quantum dots is formed in an As-enriched layer of the low-temperature GaAs by means of post-growth annealing at 400–760°C for 15 min. It is established that the AlAs barrier layer has a surface profile corresponding to that of a subbarrier layer with InAs quantum dots. The presence of such a profile causes the formation of V-shaped structural defects upon subsequent overgrowth with the GaAs layer. Besides, it was obtained that AlAs layer is thinned over the InAs quantum dots tops. It is shown that the AlAs barrier layer in the regions between the InAs quantum dots effectively prevents the starting diffusion of excess As at annealing temperatures up to 600°C. However, the concentration of mechanical stresses and the reduced thickness of the AlAs barrier layer near the tops of the InAs quantum dots lead to local barrier breakthroughs and the diffusion of As quantum dots into the region of coupled pairs of InAs quantum dots at higher annealing temperatures. [ABSTRACT FROM AUTHOR]

White-light emitting (WLE) CdSe quantum dots (QDs) capped with oleic acid (OA) were synthesized and the effects of thermal annealing and photoactivation on the small CdSe QDs in (polymethyl methacrylate) (PMMA) were investigated. A bimodal size-distribution phenomenon induced by annealing at temperatures of ∼200 °C was observed. The phenomenon observed here is different from the result of large CdSe QDs with the similar treatment. The size-dependent property arises from the fact that smaller QDs have a higher surface energy than larger ones. Annealing-induced bimodal size distribution results in a luminescence change of small CdSe QDs. [ABSTRACT FROM AUTHOR]

Shape manipulation of nanowires is highly desirable in the construction of nanostructures, in producing free-standing interconnect bridges and as a building block of more complex functional structures. By introducing asymmetry in growth parameters, which may result in compositional or microstructural non-uniformity in the nanowires, thermal annealing can be used to induce shape modification of free-standing nanowires. We demonstrate that such manipulation is readily achieved using vertically grown Pt-Ga-C composite nanowires fabricated by focused-ion-beam induced chemical vapor deposition. Even and controllable bending of the nanowires has been observed after a rapid thermal annealing in a N2 atmosphere. The mechanisms of the shape modification have been examined. This approach has been used to form electrical contacts to freestanding nano-objects as well as nano-'cages' for the purpose of securing ZnO tubs. These results suggest that thermally induced bending of nanowires may have potential applications in constructing three-dimensional nanodevices or complex structures for the immobilization of particles and large molecules. [ABSTRACT FROM AUTHOR]

La-Mg-Ni-based alloys with A2B7- and A5B19-type main phases have been prepared by step-wise annealing method at various temperatures and times. When annealing at 1173 K, the alloy is composed of (La,Mg)2Ni7 and (La,Mg)5Ni19 super-stacking phases. Increasing annealing time from 15 to 25 hours at 1173 K causes the formation of LaNi5 phase at the cost of (La,Mg)2Ni7 phase, while the (La,Mg)5Ni19 phase abundance changed very little. When the annealing temperature rises to 1223 K, (La,Mg)5Ni19 phase abundance increases drastically, indicating that (La,Mg)5Ni19 phase abundance is more affected by annealing temperature than annealing time. Electrochemical P-C isotherms show that the alloys with only super-stacking phases have single plateau. The appearance of LaNi5 phase leads to an additional plateau which becomes more obvious as LaNi5 phase abundance increases. Electrochemical measurements show that higher (La,Mg)5Ni19 to (La,Mg)2Ni7 phase ratio benefits high rate dischargeablity (HRD) and cycling stability but suppresses the discharge capacity of the alloy electrodes. Besides, with increasing LaNi5 phase from zero to 15.1 wt.% in expense of (La,Mg)2Ni7 phase, the maximum discharge capacity and cycling stability is deteriorated while the HRD, exchange current density, limiting current density and hydrogen diffusion coefficient are promoted. [ABSTRACT FROM AUTHOR]

Lithium cobalt oxide coatings on 304 stainless steel substrates have been carried out by using cathodic electrochemical synthesis in LiNO3 and Co(NO3)2 aqueous solution and subsequent annealing for thin film lithium-ion batteries. The as-deposited film is composed of the mixture of Co(OH)2•H2O and LiOH, condensed into lithium di-cobalt tetraoxide (LiCo2O4) at 310°C, and transformed into lithium cobalt dioxide (LiCoO2) and Co3O4 at 500°C, identified by X-ray diffraction (XRD) and thermal gravitational/differential thermal analysis (TGA/DTA). The two-layer structured film is observed by field emission scanning electron microscopy (FE-SEM). Cyclic voltammetry (CV) reveals the oxidation peaks at 3.75 V and 3.98 V, and the reduction peaks at 3.43 V and 3.89 V (vs. Li/Li+) for LiCo2O4 and LiCoO2, respectively. The charge/discharge test of LiCo2O4 reveals the greater reversibility and capacity at 10 μAcm-2 between 3.8 and 3.2 V (vs. Li/Li+), compared with that between 4.2 and 2.5 V. LiCo2O4, not successfully synthesized by solid state reaction at moderate temperature before, has been originally prepared by electrochemical synthesis and subsequent annealing at low temperatures (≦310°C) which could provide a suitable choice for preparing thin film lithium ion batteries applied to flexible 3C electronic products of low-cost. [ABSTRACT FROM AUTHOR]

We investigate the effect of post-growth rapid thermal annealing (RTA) on the transport and lasing characteristics of terahertz quantum-cascade lasers (THz QCLs) operating in a frequency range between 4.88 and 4.94 THz. The emission frequencies are blue shifted by about 80GHz after RTA, which is attributed to a shift of the gain maximum to higher frequencies due to composition grading at the interfaces between the quantum wells and barriers of the annealed wafer pieces. The optical output power of the annealed THz QCLs is reduced, which is explained by a broadening of the levels due to the annealing process. [ABSTRACT FROM AUTHOR]

Data retention capabilities of commercial battery-backed static random access memories (SRAMs) exposed to different ionizing dose are investigated. Pattern imprinting is observed for devices exposed to a total dose of 50 kR and above. Room temperature annealing and recovery is also recorded. A model for the pattern imprinting behavior in SRAMs is presented based on the general understanding of defects produced in MOSFETs due to ionizing radiation. [ABSTRACT FROM PUBLISHER]

The temperature dependence of the low-frequency noise of 4H-silicon carbide (SiC) MOSFETs with nitrided oxides is reported over the temperature range 85–510 K. The 1/f noise decreases significantly with increasing measurement temperature. This decrease in noise results primarily from a decrease in the density of interface traps at increasing temperatures. The 1/f noise is also characterized after total ionizing dose irradiation and postirradiation annealing. No significant change in the 1/f noise is observed after the devices are irradiated to 1 Mrad (SiO2) and then annealed under bias at elevated temperature. These results show that the 1/f noise in 4H-SiC MOSFETs is dominated by the interaction of channel carriers with slow interface traps at temperatures <360~K and with border traps >\rm\!360~K. This result contrasts with most experience with Si/SiO2-based MOSFETs, and results from the wider bandgap and greater density of slow interface traps in SiC/SiO2-based MOSFETs than in Si/SiO2-based MOSFETs. [ABSTRACT FROM AUTHOR]

In this paper, state-of-the-art laser thermal annealing is used to form germanide contacts on n-doped Ge and is systematically compared with results generated by conventional rapid thermal annealing. Surface topography, interface quality, crystal structure, and material stoichiometry are explored for both annealing techniques. For electrical characterization, specific contact resistivity and thermal stability are extracted. It is shown that laser thermal annealing can produce a uniform contact with a remarkably smooth substrate interface with specific contact resistivity two to three orders of magnitude lower than the equivalent rapid thermal annealing case. It is shown that a specific contact resistivity of 2.84\times 10^-7~\Omega\cdotcm^2 is achieved for optimized laser thermal anneal energy density conditions. [ABSTRACT FROM AUTHOR]

ABSTRACT We have studied the effect of thermal history on ionic conductivity of block copolymer electrolytes. Previous work on block copolymer electrolytes composed of polystyrene- b-poly(ethylene oxide) (SEO) and lithium bis(trifluoromethanesulfone) imide (LiTFSI) salt was restricted to lamellar morphologies. This study addresses both cylindrical and lamellar morphologies. The conductivity of low molecular weight samples decreases after they are annealed. In contrast, the conductivity of high molecular weight samples is generally unaffected by annealing. These results are explained in the context of connectivity and composition of the conducting phase. © 2013 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2013, 51, 927-934 [ABSTRACT FROM AUTHOR]

Molybdenum oxide (MoOx) has been shown to act as an efficient hole extraction layer in organic photovoltaic (OPV) devices. However, exposing MoOx films to air is problematic as it is hygroscopic; the uptake of moisture having a negative impact on its electronic properties. Here, we use spectroscopic ellipsometry to characterise the uptake of water, and fabricate PCDTBT:PC70BM based OPVs to determine its effects on device performance. We then show that thermally annealing MoOx reduces its hygroscopicity, permitting it to be processed in air. Using this process, we create air-processsed OPVs having PCEs (power conversion efficiencies) of up to 5.36%. [ABSTRACT FROM AUTHOR]

Exchange spring systems are promising for application in high performance data storage, novel permanent magnets and some other technologies. In this work, we report the exchange spring behavior in RF-annealed amorphous CoFeBSi ribbons. The measurements on magnetic and structural properties of irradiated samples revealed that the RF radiation has affected just the outermost surface layers of the ribbons. We have also reported the angular dependence of magnetization reversal and coercivity of a typical annealed sample. Our study shows that the RF annealing can be supposed to be a simple and easy manner to produce bilayer exchange spring systems. [ABSTRACT FROM AUTHOR]

Sm-Co(20 nm)/Fe(tFe) bilayers are fabricated with different Fe layer thicknesses (tFe = 0, 2, 4, 6 and 8 nm) in order to systematically investigate the intermixing effect between Fe and Sm-Co layers and its influence on the magnetic properties. X-ray diffraction analysis indicates that the deposition of soft layer (Fe) promotes crystallization of hard layer (Sm-Co) at a low annealing temperature (400 °C). The annealed films consist of hexagonal Sm2Co7, Sm2Co17 and SmCo5 phases in the hard layer and bcc-structured Fe(Co) in the soft layer. Rutherford backscattering is employed to investigate the atomic composition of the individual layers and thereby the extent of diffusion of Co atoms into the Fe layer. The estimated Co content is higher for lower tFe. The magnetic properties of the bilayers very close to the interface are analysed by the magneto-optical Kerr effect. The calculated Kerr intensities (which represent the magnetization process) are significantly affected by the extent of diffused Co in the Fe layer. Superconducting quantum interference device magnetic measurements demonstrate smooth and single-phase magnetic behaviour for tFe up to 6 nm and a good combination of high coercivity (6.5 kOe) and high magnetic remanence (834 emu cm-3) is obtained for tFe = 4 nm. [ABSTRACT FROM AUTHOR]

This work presents a study of the OSL residual signal of \Al2{\O}3\!\!:\!\!{\C} pellets after different annealing/bleaching treatments. It is shown that this luminescent material has deep trapping centers which are not associated with the TL main peaks and they are not completely emptied with an annealing up to 800^\,\circ\C. This fact was noticed when using blue light for the OSL stimulation. Optical bleaching using high power LEDs (blue, green and white) demonstrated that lower energies (green) result into higher residual OSL signal; and bleaching with similar energy (of that used for stimulation) shows better results. [ABSTRACT FROM PUBLISHER]

Measurements of the microphotoluminescence (microPL) spectra of InGaN/GaN:Sm and InGaN/GaN:Eu quantum well (QW) structures show that the action of a magnetic field gives rise to Van Vleck paramagnetism for Eu and Sm. The macrophotoluminescence (macroPL) spectra recorded after measuring the microPL spectra of InGaN/GaN QW structures doped with Sm or Eu + Sm at a high excitation level (>10 photons cm s) in magnetic fields contain no QW emission lines which are present in the macroPL spectra recorded before these microPL measurements. This is indicative of the presence of photoinduced defects. Annealing of the InGaN/GaN:Sm and InGaN/GaN:(Eu + Sm) structures reduces the concentration of photoinduced defects. [ABSTRACT FROM AUTHOR]

Interface microstructures and anomalous magnetic characteristics of HfOxfilm annealed under different conditions have been investigated using X-ray diffraction, X-ray photoelectron spectroscope, high-resolution transmission electron microscopy and superconducting quantum interference device. It is demonstrated that HfOxsamples have monoclinic crystal structure and an interface layer of Hf-silicate mixed with Hf-silicide. Remarkable ferromagnetic signals and obvious magnetic anisotropy are observed, and they are greatly affected by the post-annealing temperature and ambient. It is believed that oxygen vacancies and interface defects are responsible for the anomalous magnetic characteristics of HfOxfilms. [ABSTRACT FROM AUTHOR]

In situ measurements of static characteristics for an ad-hoc silicon-on-insulator (SOI) device represent an important method for SOI technologies characterisation. The Separation by IMplanted OXygen (SIMOX) technique is based on oxygen ions implantation into Si-film. After annealing, an increased doping concentration was reported, because of the residual oxygen clusters within the film, giving rise to oxygen thermal donors. Therefore this study offers an original algorithm for doping concentration estimation in these SOI films. A specific device used for in situ electrical characterisation of SOI wafers is the pseudo-metal oxide semiconductor (MOS) transistor. In this study, the doping concentrations extraction is based on graphical solution of a non-linear equation and third-order derivative zeroing of the measured static characteristics. In this scope, experimental curves ID–VG, in inversion and accumulation were experimentally measured for a pseudo-MOS transistor made in SIMOX technology. In this situation, the threshold and flat-band voltage are extracted, free of classical conventions. The extracted doping concentration in film is roughly 5.8 × 1015 cm-3; also the conductivity is changed from p to n in film, as the literature predicted. [ABSTRACT FROM AUTHOR]