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In this study, we present the investigation of optical properties on a series of HfS

The 2H molybdenum telluride (MoTe2) photodetector structures were made with inserting 1T-MoTe2 interlayer contacts. The optical response properties such as photoconductivity (PC) spectroscopy, illumination intensity dependent photoresponsivity, frequency dependent photocurrent, and time-resolved photoresponse were carried out in this study. In PC spectra, a much higher photoresponsivity of 2H-MoTe2 were observed by inserting 1T-MoTe2 interlayer contact. The frequency dependent photocurrent and time-resolved photoresponse investigations explore the carrier kinetic decay process of MoTe2 with different electrode contact. The Schottky barrier heights (SBH) extracted by thermionic emission theory were also investigated by inserting 1T-MoTe2 interlayer contacts. The results show the potential applicability for photodetection devices based MoTe2 layered transition metal dichalcogenides semiconductors.

Tin disulfide has substantial importance for two-dimensional material-based optoelectronics and sensors due to its unique optoelectrical properties. In this report, we fabricate SnS2 nanosheets using the low-pressure thermal sulfurization process, whose crystal structure and surface morphology are confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM) measurements. From photoconductivity measurement and photocurrent mapping, we observe smaller electrode spacing of SnS2 thin films can enhance photodetection. Then, by the H2O2 oxidation processing, we transform SnS2 to SnO2 to detect humidity. The measured response and recovery time can be optimized to 5.6 and 1.0 s, respectively, shorter than those of commercial DHT11 humidity sensor of 32 and 34 s. At suitable bias, humidity sensor can detect human respiration properly at room temperature. Our results show that SnS2 nanosheets exhibit reasonable performance for emergent photodetector applications and humidity sensing.

Intraductal papillary neoplasm of the bile duct (IPNB) is a mass-forming neoplasm in the bile duct considered to be the biliary counterpart of pancreatic intraductal papillary mucinous neoplasm (IPMN). By its cell lineage, IPNB can be classified into gastric, intestinal, pancreatobiliary, and oncocytic types. Recently, a group of Japanese and Korean pathologists proposed that IPNB be classified into two types, with type 1, being the histological counterpart of IPMN and type 2, having a more complex histological architecture. We used targeted next-generation sequencing to study the molecular change of 37 IPNBs and identified frequent mutations of KRAS (49%), GNAS (32%), RNF43 (24%), APC (24%), TP53 (24%), and CTNNB1 (11%) in IPNBs. Intestinal-type IPNB was associated with KRAS, GNAS, and RNF43 mutations. Japan-Korea consensus type 1 was associated with KRAS and GNAS mutations. All four IPNBs with CTNNB1 mutations were of pancreatobiliary type and located in the extrahepatic bile duct. A hierarchical analysis identified three distinct groups within IPNB: group 1 was Japan-Korea consensus type 1 tumors with macroscopic mucin, old age, and frequent KRAS, GNAS, and RNF43 mutations. Group 2 was Japan-Korea consensus type 2 with intestinal differentiation and frequent KRAS mutation but rare GNAS mutation, MUC2 expression, and macroscopic mucin. Group 3 was characterized by CTNNB1 mutation, extrahepatic location, lack of expression of intestinal markers, Japan-Korea consensus type 2, and lack of mutations in KRAS, APC, RNF43, and GNAS. Our results indicated that IPNB is a heterogeneous disease and that the activation of Ras-mitogen-activated protein kinase (MAPK), Wnt/β-catenin, and G-protein-coupled receptor (GPCR)-cAMP signaling is the main oncogenic mechanism of IPNB.

The MoS2/ZnO and MoS2/Si heterojunction structures were fabricated by thermal evaporation and sol-gel methods. The crystal structures properties of MoS2/ZnO and MoS2/Si were characterized by X-ray diffraction (XRD) pattern, Raman spectroscopy, and transmission electron microscope (TEM). The XRD and Raman spectroscopy results indicate that the n-MoS2 film was successfully grown on p-doped ZnO or Si. The TEM images of MoS2/ZnO and MoS2/Si heterojunction structures shows the MoS2 stacking layer-by-layer covalented by van der Waals (vdW) force. The current–voltage (I–V) measurement shows the rectifying behavior of the heterojunction structures. The photoconductivity and photoresponsivity properties explore its carrier kinetic decay process. The results shows the potential applicability of MoS2/ZnO and MoS2/Si heterojunction structures as optoelectronic devices.

Tungsten-substituted molybdenum disulfide (Mo 1 − x W x S 2 ) shows excellent semiconductor properties related to the adjustable band gap structure. Mo 1 − x W x S 2 is an n-type semiconductor that has high carrier mobility, adjustable electrical characteristics. Graphene, the thinnest two-dimensional material, shows good thermal conductivity and high carrier mobility. The oxygen adsorption effects of graphene permit precise control of its Fermi level and semiconductor properties. We combined Mo 1 − x W x S 2 films with graphene oxide (GO) in this study to fabricate a pn interface and thoroughly research the energy band and electrical properties for a heterojunction diode. According to the results, the Mo 1 − x W x S 2 electron affinity decreases with increasing x value of tungsten (W) composition (x = 0.0–1.0, Δx = 0.2). The I–V characteristics of the Mo 1 − x W x S 2 /GO heterojunction diodes can be accurately tuned by conduction band bowing effect with different W composition of the Mo 1 − x W x S 2 films. By applying our fabricating method, the Mo 1 − x W x S 2 with different W composition provides a new application of semiconductor device. In this study we using Mo 1 − x W x S 2 films and GO to fabricate a heterojunction diode, it shows different electrical properties with different x value of Mo 1 − x W x S 2 . The Mo 1 − x W x S 2 electron affinity decreases with increasing of W composition x value (x = 0.0–1.0, Δx = 0.2). The Mo 1 − x W x S 2 /GO heterojunction diode I–V characteristics can be accurately tuned using the conduction band bowing effect with different W compositions. Mo 1 − x W x S 2 with different W compositions using our fabrication method provides new semiconductor device applications.

The optical properties of WSe2-layered crystals doped with 0.5% niobium (Nb) grown by the chemical vapor transport method were characterized by piezoreflectance (PzR), photoconductivity (PC) spectroscopy, frequency-dependent photocurrent, and time-resolved photoresponse. With the incorporation of 0.5% Nb, the WSe2 crystal showed slight blue shifts in the near band edge excitonic transitions and exhibited strongly enhanced photoresponsivity. Frequency-dependent photocurrent and time-resolved photoresponse were measured to explore the kinetic decay processes of carriers. Our results show the potential application of layered crystals for photodetection devices based on Nb-doped WSe2-layered crystals.

GaAs p-i-n solar cells are studied using electroreflectance (ER) spectroscopy, light beam induced current (LBIC) mapping and photovoltaic characterization. Using ER measurements, the electric field across the pn junction of a wafer can be evaluated, showing 167 kV/cm and 275 kV/cm in the built-in condition and at &minus, 3 V reverse bias, respectively. In order to understand the effect of the interval between metal grids on the device&rsquo, s solar performance, we performed LBIC mapping and solar illumination on samples of different grid spacings. We found that the integrated photocurrent intensity of LBIC mapping shows a consistent trend with the solar performance of the devices with various metal grid spacings. For the wafer used in this study, the optimal grid spacing was found to be around 300 &mu, m. Our results clearly show the importance of the metal grid pattern in achieving high-efficiency solar cells.

Parks and green spaces have been allocated for city residents to offer them healthier natural environments. However, people living in cities may have less opportunity to engage with the natural environment since parks seem to be passive locations of activity. We investigated how to proactively enhance the attraction of green space to improve people's health. First, we surveyed how 683 city residents were engaged in physical activities. From them, 30 people were recruited for depth interviews. Results showed that the park environment and the health activities that feature ‘inner-attraction' could enhance the frequency and persistence of the city residents to engage in healthy activities. We also evaluated the service experience and attraction of 40 users in a 3-month program in the Daan Forest Park of Taipei City in Taiwan. Using the culture probes method, we found that the experience cycle and the use of social media enhanced the park's inner and inter attraction, and that the role of the park was transformed from a passive green space provider to an active service operator.

The optical anisotropy of tungsten-doped rhenium disulfide (ReS2:W) layered crystals have been studied by polarization and temperature dependent piezoreflectance (PzR) spectroscopy from 25 to 300 K. The direct band edge excitonic transitions E 1 e x feature at E∥b polarization and E 2 e x feature at E⊥b polarization of tungsten-doped ReS2 layered crystals were determined from a detailed line-shape fit of the PzR spectra. The PzR spectra reveal a slightly blue shifted of excitonic transition with the tungsten incorporation. The angular dependence of the excitonic feature amplitudes agrees with Malus' rule. The parameters that describe the temperature variation of the energies and broadening function of the excitonic transitions are determined and discussed.

Molybdenum disulfide (MoS2) films are currently the most potential semiconductor materials of the two-dimensional nano-material heterojunction. Few-layer MoS2 is an n-type semiconductor that has good mechanical strength, high carrier mobility, and has similar thickness as graphene. Graphene is presently the thinnest two-dimensional material with good thermal conductivity and high carrier mobility. The graphene Fermi level can be precisely controlled using the oxygen adsorption. Therefore, graphene can be tuned from zero-gap to p-type semiconductor material using the amount of adsorbed oxygen. In this study we combine few-layer MoS2 and graphene to produce a heterojunction and exhaustively study the interface properties for heterojunction diode application. According to the results, the MoS2 band-gap increases with decreasing thickness. The I–V characteristics of the MoS2/Graphene p-n junction diodes can be precisely tuned by adjusting different thicknesses of the MoS2 films. By applying our fabricating method, MoS2/Graphene heterojunction diode can be easily constructed and have potential to different applications.

Cadmium zinc telluride is a tunable band gap II–VI compound semiconductor, which has received considerable attention due to its applications such as nuclear radiation detectors and industrial process monitoring. We have studied the optical properties of the ternary compound semiconductors Cd1-xZnxTe grown by vertical Bridgman-Stockbarger method in the whole range of zinc content 0

The Zn1−xLixO (x = 0, 0.01, 0.03, and 0.05) nanocrystalline films were synthesized on silicon (Si) substrates by using the sol-gel method. The crystal structure and surface morphology of these films were investigated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). We observed that the average grain size was gradually reduced with increasing doping Li content. Photoluminescence (PL) spectra show that increasing the Li content will deteriorate the crystalline quality and result in the decrease of ultraviolet emission from the excitonic recombination and the enhancement of visible emission from the recombination between the intrinsic defects. The current-voltage properties of Zn1−xLixO nanocrystalline films were also studied under dark and photo-illumination for photo-detection applications. The normalized photo-to-dark-current ratio (Iphoto − Idark)/Idark has been enhanced from 315 to 4161 by increasing the Li content of the Zn1−xLixO nanocrystalline films from zero to 0.05.

Band structure engineering of two-dimensional (2D) metal dichalcogenides (TMDs) is crucial for their light-matter interaction and optoelectronic applications. Alloying of different metal or chalcogen elements with different stoichiometries in TMDs provides a versatile and efficient approach for modulating the electronic structure and properties of 2D materials. In 2D alloys, quantification of spatial distribution and local coordination of atoms facilitates the establishment of the structure-property relationship at the atomic scale. Here, we have imaged and analyzed the atomic configuration of sulfur and selenium atoms in anisotropic ReS

The aging social structure is an important issue facing the world. Due to the physiological and psychological aging of elders, various impairments and barriers affecting social events. However, with the evolution and development of information digitization, limitations, elders often come across barriers during their information system use. Thus, how to design services that meet elders' social interaction needs through the current digital information network technology remains a pressing issue for the information industry currently undergoing development.

Band structure engineering of two-dimensional (2D) metal dichalcogenides (TMDs) is crucial for their light–matter interaction and optoelectronic applications. Alloying of different metal or chalcogen elements with different stoichiometries in TMDs provides a versatile and efficient approach for modulating the electronic structure and properties of 2D materials. In 2D alloys, quantification of spatial distribution and local coordination of atoms facilitates the establishment of the structure–property relationship at the atomic scale. Here, we have imaged and analyzed the atomic configuration of sulfur and selenium atoms in anisotropic ReS1.4Se0.6 by scanning transmission electron microscopy (STEM). In Z-contrast images, we have realized the identification and quantification of Re, Se and S at different coordination sites. Different from the random distribution of metal and chalcogen elements in MoS2(1−x)Se2x and Mo1−xWxS2, we find that Se atoms preferentially locate inside of Re4 diamonds in ReS2(1−x)Se2x. Further density function theory (DFT) calculations reveal electronic structure modulation for Se occupation at different sites.

In this work, we used the chemical vapor transport (CVT) method to grow PbI2 crystals using iodine as a self-transporting agent. The crystals&rsquo, structure, composition, and uniformity were confirmed by X-ray diffraction (XRD) and electron probe microanalysis (EPMA) measurements. We investigated the band gap energy using absorption spectroscopy measurements. Furthermore, we explored the temperature dependence of the band gap energy, which shifts from 2.346 eV at 300 K to 2.487 eV at 20 K, and extracted the temperature coefficients. A prototype photodetector with a lateral metal&ndash, semiconductor&ndash, metal (MSM) configuration was fabricated to evaluate its photoelectric properties using a photoconductivity spectrum (PC) and persistent photoconductivity (PPC) experiments. The resonance-like PC peak indicates the excitonic transition in absorption. The photoresponse ILight/IDark-1 is up to 200%.

The structural and optical properties of Cu-poor CuIn 1− x Ga x Se 2 thin films with different gallium contents grown using the co-evaporated technique were studied. Measurements of X-ray diffraction (XRD), temperature-dependent photoluminescence (PL), and photoreflectance (PR) were performed on the samples. The emission peaks in the PL spectra and PR spectra observed around 1.0–1.2 eV are attributed to donor–acceptor pairs and defect-related luminescence. With increasing gallium content, the linewidths of the luminescence spectra for the samples become wider, which we attribute to greater statistical disordering between indium and gallium. The structural properties of the CuIn 1− x Ga x Se 2 thin films are further characterized by simulation of the XRD spectra with a theoretical model. It is found that the sample with higher gallium content exhibits less uniformity of microstructure size. The X-ray diffraction line profile analysis also shows a stronger internal strain in the sample with the higher gallium content, which is consistent with its broader microstructure size distribution. The conversion efficiency of the CuIn 1− x Ga x Se 2 -based solar cells is also obtained and investigated through theoretical analysis. The experimental results coincide with the inferences given by the X-ray diffraction line profile analysis.

National Science Council of Taiwan [NSC 100-2112-M-011-001-MY3, NSC 100-2221-E-131-005-MY2]; National Basic Research Program of China [2012CB933503]; National Natural Science Foundation of China [61036003, 61176092]

2D black phosphorus (BP) and rhenium dichalcogenides (ReX

Cardiac myxoma is the most common cardiac tumour. Most lesions occur sporadically, but occasional lesions develop in patients with Carney complex, a syndrome characterized by cardiac myxoma, spotty pigmentation, and endocrine overactivity. Two-thirds of patients with Carney complex harbour germline mutations in PRKAR1A, which encodes the type I regulatory subunit of protein kinase A (PKA). Most studies have not found a mutation in PRKAR1A in sporadic cardiac myxoma cases. Recent studies identified frequent mutations in PRKACA, which encodes the catalytic subunit of PKA, in cortisol-secreting adrenocortical adenoma cases. To determine whether the PRKACA mutation is involved in the tumourigenesis of cardiac myxoma, we performed Sanger sequencing of 41 specimens of sporadic cardiac myxoma to test for the presence of mutations in the coding regions and intron-exon boundaries of PRKACA. Mutations were identified in four cases (9.7%). In contrast to the point mutations identified in adrenocortical adenoma, all mutations were in-frame microinsertions of 18-33 bp clustered in exons 7 and 8. The mutated PRKACA proteins lost their ability to bind to PRKAR1A, and thereby lead to constitutive activation of the PKA pathway. Together with previous reports of PRKAR1A mutations in syndromic cardiac myxoma, our study demonstrates the importance of the PKA pathway in the tumourigenesis of cardiac myxoma. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John WileySons, Ltd.

In this work, the hydrothermally grown ZnO nanostructures were successfully prepared using the aqueous solution of zinc nitride dehydrate (Zn(NO3)2). The effect of solution molarity on the optical and structural properties of ZnO nanostructures were studied by temperature dependent photoluminescence (PL) measurements. The intensity ratio of the ultraviolet emission to the visible emission is calculated. It is found that the calculated results are also dependent on the solution molarity and consistent with the crystal quality of ZnO nanostructures.

ZnO and indium-doped ZnO structures were prepared by hydrothermal method deposited for different time duration. Scanning electron microscopy (SEM) measurements show that flower-like crystals form during the synthesis. X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) measurements confirm the incorporation of the dopant ion into the crystalline lattice of ZnO. The effects of indium doping on the optical properties of ZnO structures were studied by temperature dependent photoluminescence (PL) measurements. Observing the measured results, the samples show visible emission in the region of 1.8 eV and the PL intensities increase for indium-doped samples. Solar cells were prepared by immersing the samples into N-719 dye solution. From the measured photocurrent-voltage characteristics, we obtain that power conversion efficiency improved for indium-doped ZnO samples. It is found that the indium-doping acting as an important role in the formation of ZnO structures and the resulted power conversion efficiency of dye-sensitized solar cells.

The results of Raman scattering of zinc-blende Zn1-x-yMgyBexSe mixed crystals are reported. From analyzing the polarized Raman spectra, longitudinal and transverse phonon modes corresponding to ZnSe-like, MgSe-like and BeSe-like optical phonon modes are identified. The observed optical phonon modes of the mixed crystals in the BeSe-like spectral region provides experimental evidence that the 1-bond 2-mode percolation scheme may apply to the investigated quaternary mixed crystals. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

An optical study of wurtzite Zn0.35Cd0.44Mg0.21Se crystalline alloy grown by the modified high-pressure Bridgman method was carried out by polarization-dependent contactless electroreflectance (CER) and temperature-dependent photoluminescence (PL) in the temperature range of 10–300 K. The CER experiment revealed three well known wurtzite crystal lattice related excitonic features A, B, and C in the vicinity of band edge. The excitonic features A and B showed polarization-dependent character, where both A and B excitons are present for E⊥c polarization and only B exciton is observed for E‖c polarization. Low temperature PL spectra of the investigated sample consisted of the excitonic line, the “edge emission” due to radiative recombination of shallow donor-acceptor pairs and a broad band related to recombination through deep level defects. In addition, the transition energies and broadening parameters of the band-edge excitonic transitions were evaluated and discussed. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We report on the structural and material properties of Cu-poor CuIn1-xGax Se2 (CIGS) thin films with different gallium contents grown using the co-evaporation technique. Temperature-dependent photoluminescence (PL) and high-resolution X-ray diffraction measurements were performed. The PL emission peaks observed around 1.0-1.2 eV are attributed to donor-acceptor pair luminescence. These donor-acceptor pair emissions are considered to originate from relatively shallow acceptor and donor energy levels. In addition, the X-ray diffraction spectra of the samples are simulated using a theoretical model. From the analysis, it is found that the sample with higher gallium content exhibits smaller grain size and the microstructure size uniformity is reduced. The theoretical calculation result is consistent with the experimental results derived from the PL spectra. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A steady-state thermal model is presented to investigate the temperature and injection-current dependence of the electroluminescence (EL) in InGaN/GaN multiquantum-well light-emitting devices. The important mechanisms for the carrier dynamics, including thermal emission, recapturing, radiative and nonradiative recombination, are taken into account in this model. From the measured EL spectra, it is found that the S-shaped temperature dependence of the peak energy disappears at a high injection-current level. The temperature-dependent emission energies of the EL spectra are calculated with this model. The band-filling effect and the heating effect are considered in our investigation of this phenomenon, and the simulation results are in fair agreement with the experimental data. It is observed that both the band-filling and heating effects influence the temperature dependence of the EL emission spectra of InGaN/GaN multiquantum-wells. Quantitative discussion reveals that the heating effect becomes more apparent when the device is working at high injection-currents.

We report the deposition and structural characterization of nanostructural RuO2 on rutile (R)-TiO2/sapphire(100) templates by reactive radio frequency magnetron sputtering. The micrographs of field-emission scanning electron microscopy and X-ray diffraction patterns of RuO2/R-TiO2 heteronanostructures indicated the growth of vertically aligned RuO2 (001) nanotubes (NTs) and/or V-shaped RuO2(101) nanowedges (NWs) on top of R-TiO2 nanorods (NRs). Transmission electron microscopy and selected-area electron diffractometry characterizations of the vertically aligned RuO2 NTs showed that the hollow RuO2 NTs with square cross section have open-end morphology with long axis directed along the [0 0 1] direction, while the V-shaped RuO2 NWs revealed that the nanowedges are crystalline RuO2 with twin plane of (101) and twin direction of 1 ¯ 01 at the V-junction. The probable mechanisms for the formation of well-aligned RuO2 nanocrystals on top of R-TiO2 NRs were discussed.

We report the growth of well-aligned RuO2/R-TiO2 heteronanostructures on sapphire (100) substrates by reactive magnetron sputtering using Ti and Ru metal targets under different conditions. The surface morphology and structural properties of the as-deposited heteronanostructures were characterized using field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected-area electron diffractometry (SAED). The FESEM micrographs and XRD patterns indicated the growth of vertically aligned RuO2(001) nanotubes and twinned V-shaped RuO2(101) nanowedges (NWs) on top of R-TiO2 nanorods under different sputtering pressures. TEM and SAED characterizations of the V-shaped RuO2 NWs showed that the NWs are crystalline RuO2 with twin planes of (101) and twin direction of [ 01] at the V-junction.