Yi Ben Xia

Growth of ZnS Films and Application in Heterojunction

ZnS films were prepared by radio-frequency (RF) magnetron sputtering method. The effects of substrate temperature and annealing treatment on the properties of ZnS films were studied. The ZnS films were characterized by X-ray diffraction (XRD), UV-visible spectrophotometer, and electrical measurements. The results showed that the higher substrate temperature and post-deposition annealing treatment was helpful in improving the crystalline quality of the films, and the film had an n-type conductivity. N-type ZnS films were also deposited on p-type single-crystalline silicon (Si) substrates to fabricate ZnS/ Si heterojunction. The current-voltage (I-V) characteristic of the heterojunction was examined, which showed a rectifying behavior with turn-on voltage of about 2V.

Te Inclusions in CdMnTe Crystal Grown by the Traveling Heater Method and their Effects on the Electrical Properties

The concentration and size distribution of Te inclusions in CdMnTe (CMT) are key factors in nuclear devices performance. High-concentration and large-size Te inclusions degrade the performance drastically, especially for electrical properties. In this paper, the Te inclusions along the axial and radial directions in CMT crystal grown by the Traveling Heater Method (THM) were revealed by Infrared Microscopic System. The size of Te inclusions is 5-17 μm and the concentration is (2.5-4.6) ×105 cm-3. The Current-Voltage measurements were performed and the resistivity of the CdMnTe crystal with excess Te was in the range of 108-109 Ωcm, and the correlation between the Te inclusions and resistivity was investigated. The large size (>17 μm) and high concentration (4.5 of ×105 cm-3) Te inclusion decrease the resistivity of the CMT crystal seriously.

Properties of Li-Doped ZnO Films Deposited on Diamond Films

Li-doped zinc oxide (ZnO) films were deposited on nucleation side of freestanding diamond (FSD) films by the radio frequency magnetron sputtering method. The effect of oxygen partial pressure on structural, optical and electrical properties of the ZnO films was investigated by X-ray diffraction (XRD) Raman spectroscopy, semiconductor characterization system and Hall effect measurement system. The results showed that the introduction of oxygen as a reactive gas was helpful to improve the crystalline quality of Li-doped ZnO films.

Effect of Oxygen Partial Pressure on Properties of ZnO Films Deposited on Freestanding Diamond Films

Highly c-axis-oriented ZnO films were deposited successfully on the nucleation sides of freestanding diamond (FSD) films by the direct current (DC) magnetron sputtering method in an oxygen (O2) + argon (Ar) gas mixture. The effect of oxygen partial pressure on properties of ZnO films was investigated by X-ray diffraction (XRD). The results showed that when flux ratio of argon to oxygen was 1, the ZnO films had a better crystalline quality.

Microstructure and Electrical Characterization of In-Doped Cd0.9Mn0.1Te Crystal Grown by the Vertical Bridgman Method

CdMnTe is one of the key materials for room temperature X-ray and gamma-ray detectors on Environmental Analysis and Monitoring. In this paper, the homogeneous Cd1-xMnxTe (x = 0.1) single crystal ingot was grown by the vertical Bridgman method. The compositional analysis was carried out by SEM/EDS. The Te inclusions were revealed by the IR transmission spectra. In dopant distribution was determined by ICP-AES measurement. The resistivity of CdMnTe was cha-racterized by I-V method. It was found that the segregation coefficient of Mn was 0.97. In dopant contents within 3 to 21 ppm of the ingot were found. The Te inclusions were mainly 8.2-28.3uf06dm in size and 1×105-1.5×107cm-3in concentration. I–V measurement reveals that sputtered Au film can form good ohmic contact and all the slices have the resistivity within 107 to 109Ωuf0d7cm.

Impact of the Oxygen Content on the Electronic Properties in Epitaxial Thin Films of Electron-Doped La0.9Hf0.1MnO3

Thin films of perovskite manganite La0.9Hf0.1MnO3 (LHMO) have been grown on (100) SrTiO3 single-crystal substrates with different growth pressures by pulsed laser deposition. The different transport behaviors of films have been fitted by various models. The results clearly demonstrate that oxygen pressure is an efficient way to change the transport behaviors of LHMO films. All the transport behaviors observed in LHMO films can be better fitted by Mott’s variable range hopping model than the other two models.

Effect of Deposition Temperature on Surface Roughness of Nanocrystalline Diamond Film

Nanocrystalline diamond (NCD) films were synthesized by hot-filament chemical vapor deposition (HFCVD) method at different temperatures (600 °C, 620°C, 640°C and 660°C). The AFM and Raman analyses demonstrated that deposition temperature has a great effect on the surface roughness and quality of NCD films and 620°C is the temperature to grow NCD films with smooth surfaces.

A Threshold Voltage Simulation of Hydrogen-Terminated Diamond MESFETs

In this paper, the threshold voltage of diamond film-based metal-semiconductor field effect transistors (MESFETs) has been simulated using Silvaco TCAD tools. The drain current (Id) versus gate voltage (Vg) relationship, and the distribution of acceptors in diamond surface conduction layer were also investigated. From the simulation results, it was found that the gate length contributed the most to the threshold voltage, while the doping depth almost had no impact on the threshold voltage value.

Characterization of Indium-Doped CdZnTe Crystal Grown under Te-Rich Conditions

CdZnTe (CZT) crystals with a diameter of 52 mm was grown using low pressure Bridgman method and were indium-doped under Te-rich conditions. Results showed the Te concentration was almost the same in different part of the as-grown ingot. Through IR transmission, Te inclusion with regular triangular or circular shapes could be observed, and the size of Te inclusion was around 7 µm and the concentration was 1.5 uf0b4 105 cm-3 for the CZT in the middle part of the ingot. I-V characteristic showed a good linear behavior with a resistivity of ~1010 Ω•cm.

ZnO Films Deposited on Various Diamond Film Substrates with Different Surface Roughness

ZnO thin films were deposited by radio frequency (R. F.) magnetron sputtering on various diamond film substrates with different surface roughness. The influence of surface roughness on structural properties and surface morphology of ZnO thin films was investigated by X-ray diffraction (XRD) and atom force microscopy (AFM), respectively. Only on the nanocrystalline and free-standing diamond substrates, ZnO films with preferential c-axis orientation and smooth surface were obtained.