Yang Liao

Thin film poly-crystalline silicon fabrication based on Rapid Thermal Annealing (RTA) process

Rapid Thermal Annealing (RTA) process was introduced to the experiment of Aluminum-induced crystallization of a-Si, based on sputtering method, on low cost glass substrate. A stack of glass/Al (150 nm)/Si (220 nm) was deposited by sputtering sequentially. Samples were annealed under RTA process, then annealed in the tube annealing furnace at 400 °C for 5 h. The grain crystallization was inspected by optical microscopy (OM), ,Raman spectroscopy, X-ray diffraction (XRD)，and energy dispersive spectroscopy (EDS). The preferential orientation (111) was observed, with a Raman Peak at 520.8cm-1, Different annealing periods were discussed.

Electrical properties of polycrystalline mercuric iodide detector

Potentially low cost and large area polycrystalline mercuric iodide is one of the preferred materials for the fabrication of room temperature X-ray and gamma-ray detectors. The properties of the contact between electrode and film play an important role in the performance of the polycrystalline mercuric iodide detector. The crystalline structure of the as-deposited polycrystalline α-HgI2 films were characterized by XRD. The surface morphology of the films was obtained by optical microscope and scan electron microscopes (SEM). And the I-V curve and the response to 241Am were measured after evaporating Au electrode. The energy resolution of 241Am α particles at room temperature was obtained.

Investigation of Se supply for the growth of CZTSSe thin films for photovoltaics

In this work, the selenization growth of Cu2ZnSn(SxSe1−x)4 (CZTSSe) films was optimized by two groups of experiments in vacuum chamber. The selenization of CZTSSe is strongly dependent on the Se supply in the vacuum chamber. Insufficient Se supply left the selenization incomplete. Higher Se supply to CZTSSe either by increasing the Se powder usage or by increasing the external pressure resulted in the degradation of CZTSSe films with lower degree of crystallinity.The characterization of XRD, Raman and SEM confirmed the films obtained under the best conditions were well-developed CZTSSe films with compact faceted grains and good crystallinity. Additionally, theCZTSSe film grown using 500°C showed more orientation along (220).

Preparation and Properties of ZnO@ZnS Nano-Array Core-Shell Structure with Different Concentration of TAA

ZnO@ZnS nano-array core-shell structure was synthesized through a solution method using a thioacetamide (TAA) solution in deionized water. The as-synthesized ZnO nano-array and TAA solution were employed to supply zinc and sulfur ions to form the ZnO@ZnS core-shell structures. The properties of the structure were characterized by X-ray diffraction (XRD), Raman spectrum, scanning electron microscopy (SEM) and UV-Vis spectra. The results indicate that ZnO nano-array was coated with ZnS particles. The concentration of TAA solution can affect the diameter, surface roughness and optical properties of the ZnO@ZnS nano-array core-shell structures.

Properties of Ohmic Contact of Au Electrode on Polycrystalline Mercuric Iodide

Polycrystalline mercuric iodide films are being developed as a new detector technology for digital X-ray imaging. The properties of the contact between electrode and film play an important role in the performance of the polycrystalline mercuric iodide detector. In this paper, the films were grown on the thin film transistor (TFT) substrates via hot-wall physical vapor deposition method. Au front contacts were deposited onto the HgI2 films by thermal evaporation under a vacuum of 10-4Pa. The HgI2 films were characterized by X-ray diffraction (XRD). The surface morphology of the films before and after the process of evaporating Au was compared by scan electron microscopes (SEM). And the I-V curve was measured after evaporating Au electrode. The results indicate that the polycrystalline mercuric iodide films we prepared have a very strong (001) growth-preference. Au was deposited on the grain surface forming excellent ohmic contact with polycrystalline α-HgI2 film which was also confirmed by the I-V characteristic of HgI2 film after the process of evaporating Au electrode.

Preparation and Properties of Cu2ZnSnS4 Nanoparticles by Solvothermal Method

Earth-abundant Cu2ZnSnS4(CZTS), a promising alternative photovoltaic material, was prepare by a mild solvothermal route and annealed. The as-prepared nanoparticles were obtained at 200°C and analyzed by X-ray diffraction(XRD). The crystallinity of CZTS particles was greatly improved by annealing in N2 gas shown in XRD. EDS results indicate the composition of the film and the variety of the ratio of the metal atoms and S atoms.

Aluminum-Induced Crystalization of Amorphous Silicon Films Deposited by Megnetron Sputtering

Aluminum–induced crystallization of sputtered a-Si under two-step annealing procedure on glass substrate is studied. A 200 nm thick a-Si film was deposited by magnetron sputtering on glass and a Al film of 150 nm was sputtered on top. The samples were annealed under two-step annealing procedure. Nucleation and growth of grains were followed by optical microscopy (OM), X-ray diffraction (XRD), Raman spectroscopy, and energy dispersive spectroscopy (EDS). Continuous (111) oriented poly-Si films were obtained with a Raman Peak at 520.8cm-1. The different annealing periods is discussed.

Growth Time Influence on Polycrystalline α-HgI2 Films

Polycrystalline α-HgI2 films have been grown on TFT substrates using hot-wall vapor phase deposition (HWPVD) with the different growth times. The influence of different growth times (1 hour, 2 hours, 3 hours, 4 hours) on the structural and electrical properties of the polycrystalline α-HgI2 films is investigated. Metallurgical microscope, scan electron microscopes (SEM) and X-ray diffraction (XRD) characterization and the electric transport properties were investigated by the I-V characteristics. The polycrystalline α-HgI2 films growth by 3 hours show more better performance than others. So we use it preparation a detector.Finally, capacitance frequency characteristics analysis showed the detector have good performance.

Preparation of polycrystalline silicon thin films on glass by aluminium-induced crystallization

Polycrystalline silicon (p-Si) is well-known as the high-efficency, low-cost, and most ideal material for manufacturing photovoltaic devices. In recent years, excimer-laser annealing (ELA), metal-induced crystallization (MIC) and solidphase crystallization (SPC) methods are employed to crystallize amorphous silicon (a-Si). In this paper, a cheap metal induced crystallization method of fabricating p-Si thin films on an ordinary glass substrate was investigated. In this synthesis process, a-Si thin film has been deposited onto glass substrates by Plasma Enhanced Chemical Vapor Deposition (PECVD), and p-Si thin films have been fabricated by aluminium-induced crystallization (AIC) under nitrogen ambient. The effects of annealing time, annealing temperature on the crystallization of a-Si were investigated by X-ray diffraction (XRD) technique. Our results indicate that annealing temperature over 300°C is necessary for crystallization of a-Si which preferred to orientation crystalline Si(111) and this preferred orientation becomes more obvious as increasing of annealing time and annealing temperature. Meanwhile, the longer annealing time can produce more a-Si crystallize completely under same aluminium thickness and annealing temperature.

Preparation of polycrystalline silicon thin films on glass by aluminiuminducedcrystallization

Polycrystalline silicon (p-Si) is well-known as the high-efficency, low-cost, and most ideal material for manufacturing photovoltaic devices. In recent years, excimer-laser annealing (ELA), metal-induced crystallization (MIC) and solidphase crystallization (SPC) methods are employed to crystallize amorphous silicon (a-Si). In this paper, a cheap metal induced crystallization method of fabricating p-Si thin films on an ordinary glass substrate was investigated. In this synthesis process, a-Si thin film has been deposited onto glass substrates by Plasma Enhanced Chemical Vapor Deposition (PECVD), and p-Si thin films have been fabricated by aluminium-induced crystallization (AIC) under nitrogen ambient. The effects of annealing time, annealing temperature on the crystallization of a-Si were investigated by X-ray diffraction (XRD) technique. Our results indicate that annealing temperature over 300°C is necessary for crystallization of a-Si which preferred to orientation crystalline Si(111) and this preferred orientation becomes more obvious as increasing of annealing time and annealing temperature. Meanwhile, the longer annealing time can produce more a-Si crystallize completely under same aluminium thickness and annealing temperature.