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In this paper, the CdMnTe crystals were grown by the Travelling Heater Method (THM) and the Vertical Bridgman (VB) method, respectively. The crystal properties, including the Mn axial distribution, impurity concentrations, resistivity, Hall effects and energy response spectra, were characterized and compared. The results shown that the CdMnTe crystal grown by the THM had more uniform Mn distribution and lower impurity concentrations compared to the crystal grown by VB method. The resistivity of CdMnTe grown by THM was (1.5 ∼ 8) × 1010 Ω.cm, while the resistivity of CdMnTe grown by VB was 107∼108 Ω.cm. The In dopant distributed uniformly throughout the crystal ingot grown by THM with the doping concentration of 0.6-0.7 ppm, while the In dopant concentration throughout the crystal grown by VB method is in the range of 1.31-2.4 ppm. Hall measurements revealed that the conductivity of the THM grown crystal was weak n-type conductivity and the VB grown crystal was p-type conductivity. A planar CdMnTe detector from the THM grown crystal showed a resolution of 8% of the 241Am radiation at 59.5 keV peak, however, no energy response was revealed with the CdMnTe detector by the VB method. The results demonstrate that CdMnTe crystal grown by THM have better crystal quality and detector properties compared to that by VB method. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we developed X-ray radiation detectors with sandwich structure fabricated from nano-crystalline diamond (NCD) films. These NCD films with different grain size ranging from 15nm to 160nm were grown on silicon substrates using a hot-filament chemical vapor deposition technique. I–V measurement results indicate that with reducing of the grain size, the resistivity of diamond films decreases from 9.5×108 to 6.20×107 Ωcm and the ratio of the photocurrent to the dark-current (I ph /I d ) of the detectors decreases rapidly from 0.45 to 0.09 at an electric field of 50kV/cm. Typical spectral response to 5.9keV 55Fe X-rays shows that counting efficiency and energy resolution of NCD detectors with large grains are better than those of detectors with small grains, due to the less defects and grain-boundaries contained in the film. [Copyright &y& Elsevier]

Abstract: The effect of the polarity of the applied bias voltage on the electrical response and the charge collection efficiency of sandwich structural diamond film detectors under 5.5 MeV 241Am alpha-particle irradiation is investigated. Results show that, under the alpha irradiation the detector applied with a negative bias voltage has a higher response current and a better signal-to-noise ratio than that applied with a positive bias voltage. A better energy resolution of about 25.0% is obtained for the detector applied with a negative bias voltage, and however 38.4% for that with a positive bias voltage. Raman scattering studies demonstrate that these changes with the polarity of the bias voltage may be attributed to the different structural imperfection distributions along the thickness direction of the diamond film. [Copyright &y& Elsevier]

An undoped p-type nanocrystalline diamond (NCD) film was grown by an electron assisted hot filament chemical vapor deposition (EA-HFCVD) technology on an n-type single-crystalline Si substrate to fabricate p-NCD/n-Si heterojunction. The structure and morphology of the NCD film, which was analyzed by Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM), showed that the film consisted of 40–60 nm polycrystalline nano-grains. The results showed that with EA-HFCVD method, not only an undoped NCD film with high conductivity but also a p–n heterojunction diode between the NCD film and n-Si substrate was fabricated successfully. The p-NCD/n-Si heterostructure was also used for ultraviolet (UV) photodetector application. Operating at a bias voltage of 10 V, this photodetector showed a significant discrimination between UV and visible light, and the UV/visible-blind ratio was about three orders of magnitude. [ABSTRACT FROM AUTHOR]

ZnTe materials exhibit distinctive characteristics that render them exceptionally suitable for the utilization in circumventing the electrode contact issue for the CdZnTe based devices for photoelectric applications. This work employed the co-sputtering technique to fabricate ZnTe:Cu films, probing the influences of Copper (Cu) sputtering power on the film's structural, morphological, optical, and electrical properties. It is disclosed that the sputtering power of the Cu target leads to a proportional increase in Cu x Te compounds within the ZnTe:Cu films. Notably, an increase in the sputtering power of the Cu target is found to enhance the carrier concentration of the film, but not decrease the resistivity. This unnormal arose is due to a substantial reduction in carrier mobility at higher Cu target sputtering powers. The ZnTe:Cu film exhibits relatively lower resistivity when the sputtering power of the Cu target is approximately 3 W. The optimized ZnTe:Cu film as a buffer layer for the electrode is favor of remarkable improving the ohmic contact properties between the electrode and the CdZnTe, exhibiting a low contact resistivity of 0.62 Ω cm2. This work offers a promising approach to ameliorate the contact performance for the CdZnTe devices with high performance and high reliability. • ZnTe:Cu films were fabricated through co-sputtering method. • Effects of sputtering power of Cu target on the properties of ZnTe:Cu films were examined. • ZnTe:Cu film as a buffer improves ohmic contact between electrode and film. [ABSTRACT FROM AUTHOR]

Abstract: The optical and electrical properties of variously textured diamond films have been investigated in this paper. SEM and Raman spectrum indicated that the films produced were of high quality with either (001) or (111) orientation. A four-layer model was used to fit the measured spectroscopic ellipsometry data. The results indicated that the properties of (001)-oriented diamond films were superior to those of (111)-oriented one. The refractive index and extinction coefficient of (001)-oriented diamond film in the infrared region of 2500–12500nm was measured as 2.391 and of the order of 10−5, respectively and that for (111)-oriented one was 2.375 and of the order of 10−4, respectively. The dark current of the (001)-oriented diamond film was measured as 33.7nA for an applied electric field of 100kVcm−1, its resistivity being about 2.33×1010 Ωcm. Current passing through the (001)-oriented diamond film during testing did not change significantly. [Copyright &y& Elsevier]

Abstract: Due to different oriented diamond films having different properties, in this paper optical and electrical properties of different oriented diamond films have been investigated. The measured results indicate diamond films are of high quality and the properties of the (001)-oriented diamond film are better than those of the (111)-oriented one. Refractive index and extinction coefficient of (001)-oriented diamond film in the wavelength range of 2.5–12.5μm is 2.391 and in the order of 10−5, respectively. And for the (111)-oriented one it is 2.375 and in the order of 10−4. The dark current of the (001)-oriented diamond film is 33.7nA under an applied electric field of 100kV/cm. The resistivity of the (001)-oriented diamond film obtained is about 2.33×1010 Ωcm. The current of (001)-oriented diamond film is almost no change with the time testing. [Copyright &y& Elsevier]

Abstract: We reported the growth and its electrical properties of [100]-oriented diamond film using alcohol and hydrogen by HFCVD. SEM and Raman measurements indicated that high quality polycrystalline diamond films with [100]-faced structure were obtained. Dark current–voltage (I–V), capacitance–frequency (C–F), capacitance–voltage (C–V) and photocurrent under steady-state 55Fe 5.9keV X-ray excitation of freestanding diamond film were investigated at room temperature. Results indicated that after post-annealing for [100]-oriented diamond films dark current was in the order of 10−10 A and the photocurrent was of in the order 10−8 A by X-ray irradiation with the applied voltage of 40V, capacitance and dielectric loss were very small with the value of 2pF and 2×10−3 with the bias voltage of 0.05V, respectively, and almost had no variation with the change of frequency in high frequencies from 100kHz to 10MHz. [Copyright &y& Elsevier]

SnS nanobelt thin films were deposited on glass substrates in acidic solution by chemical bath deposition (CBD) method. The belt-like morphologies of as-deposited SnS thin films were characterized by scanning electron microscope (SEM) and transmission electron microscopy (TEM). X-ray diffraction (XRD) and Raman measurements were carried out to confirm the crystal structures and phase purities of SnS nanobelt thin films. The morphologies and phase purities of SnS thin films were influenced greatly by the tin and sulfur precursors. The bandgaps of SnS nanobelts were determined to be 1.39–1.41 eV by UV–vis absorption and photoluminescence (PL) spectra. Current-voltage ((I V)) and current-time ((I-T)) characteristics were studied to demonstrate the photoelectric performances of SnS nanobelt thin films. [ABSTRACT FROM AUTHOR]

Ga 2 O 3 is a promising ultra-wide bandgap semiconductor as a feasible candidate for power electronics, photodetectors, and sensors. Controlling electrical properties through doping is the key to its application in semiconductor devices. In this work, Ta-doped Ga 2 O 3 films were prepared by radio frequency (RF) magnetron sputtering with seed layers. Effects of the thickness of seed layers on the microstructure, morphology, optical and electrical properties of Ta-doped Ga 2 O 3 films were investigated. The fabricated Ta-doped Ga 2 O 3 films exhibited polycrystalline structure with uniform and smooth surface and high optical transmittance (＞80 %) in the visible light region. The results showed that seed layers with appropriate thickness (∼20 nm) is beneficial to the improvement of crystalline quality and electrical properties of Ta-doped Ga 2 O 3 films. [ABSTRACT FROM AUTHOR]

Highlights • Nanocrystalline diamond films (NCDs) have been grown on Si substrates by HFCVD. • NCD was treated by hydrogen plasm etching with varying time. • The dark current can be suppressed by the hydrogen etching treatment. • NCD with 3 h hydrogen etching exhibited dielectric constant close to intrinsic diamond and low dielectric loss. Abstract The nanocrystalline diamond (NCD) were synthesized on silicon substrates by a hot filament chemical vapor deposition (HFCVD) method with varying hydrogen plasma etching time. The hydrogen etching effect on the characteristics of current-voltage, capacitance-frequency and dielectric loss-frequency have been studied. It was founded that the dark current decreased with the etching time. The dielectric properties based on NCDs can be improved with the increasing in etching time, indicating sample with 3 h hydrogen etching exhibited dielectric constant closed to intrinsic diamond and low dielectric loss. The hydrogen etching treatment can provide a feasible approach to enhance the dielectric property of NCD. [ABSTRACT FROM AUTHOR]

Polycrystalline mercuric iodide films are being developed as a new detector technology for X-ray imaging at room temperature. Polycrystalline mercuric iodide (HgI 2 ) films have been grown on ITO-coated glass substrates using hot-wall physical vapor deposition (HWPVD) with the different source temperatures. The electrical properties of high quality polycrystalline HgI 2 detector based on coplanar-grid electrode are investigated at room temperature. The HgI 2 device of high quality polycrystalline films has low leakage current before X-ray radiation and stable capacity under low frequency. Different coplanar-grid electrode patterns are designed by varying the widths of grid and gap. The finite elements analysis is used to simulate the potential distribution of the coplanar-grid HgI 2 device. The electrode design of pattern A (the width of grid is 150 μm and the width of gap is 500 μm) is the best. The electrical characteristic of coplanar-grid device using mask A verifies the feasible simulation of electrode design for pattern A. [ABSTRACT FROM AUTHOR]

In recent years, Ga 2 O 3 has attracted extensive attention at home and abroad due to its excellent properties. In this paper, Ta-doped Ga 2 O 3 films were grown on quartz substrates by magnetron sputtering technique. Effects of substrate temperature and seed layer on the performance of the films were investigated. The results showed that all films had uniform, smooth surface morphology and better transparency (>85%) in the wavelength region of 300–800 nm. Hall effect measurement revealed low resistivity of 0.089 Ω cm and high carrier concentration of 2.4 × 1019 cm−3 for the Ta-doped Ga 2 O 3 film grown with seed layer. XPS spectra demonstrated that Ta was incorporated into the Ga 2 O 3 films and Ta5+ ions were obtained. [ABSTRACT FROM AUTHOR]

Abstract: The outstanding properties of mercury iodide make it an ideal material as room temperature X-ray and gamma-ray detectors. For this purpose, electrical and irradiation properties of high quality polycrystalline HgI2 detector are investigated at room temperature under irradiation conditions by 5.9keV X-ray irradiation from a 55Fe source. For (001)-oriented polycrystalline HgI2 film, the dark current is in the order of 10−10 A and photocurrent is in the order of 10−9 A with the applied voltage of 40V. However, a good signal to noise ratio of 4.44 and an energy resolution of 4.1% for X-ray detecting is also obtained. [Copyright &y& Elsevier]

• CZT micro pillar films have been deposited by CSS method. • The morphologies of CZT micro pillar films were modulated by deposition times. • Photo-electronic properties of CZT micro pillar films were investigated. CdZnTe (CZT) micro pillar films with cubic zinc blend phase have been deposited on single layer graphene coated quartz substrate by close-spaced sublimation technique. Structural and phase purities of deposited micro pillar CZT films were investigated using X-ray diffraction and Raman spectroscopy. Scanning electron microscopy characterizations indicated that the diameters of CZT micro pillars were about 5 µm and their lengths were close to 57 µm. The band-gap of CZT micro pillar films was about 1.53 eV, which was confirmed by UV–Vis–NIR diffuse reflection spectra and PL spectra. The structure of Au/BGZO/CZT/graphene/quartz was fabricated to study its optoelectronic properties. Under the illumination of AM 1.5, CZT micro pillar films had good photo response, which indicated their great potential in the application of optoelectronic devices. [ABSTRACT FROM AUTHOR]