Papers by Author: Bo Huang

Abstract: The Ga-doped ZnO thin films (GZO) were deposited at room temperature by DC magnetron reactive sputtering. The influence of vacuum annealing temperature on the morphology, internal stress, optical and electrical properties were investigated. The results showed that with the rise of annealing temperature, the grain size increased, the preferred orientation and crystallization degree became better, the internal stress reduced, the resistivity firstly decreased slightly before 350°C and then increased sharply. The minimum resistivity of 1.32×10^-3Ω•cm was obtained at 350°C. The annealing temperature had a very big influence on the transmittance, and the average transmittance was about 80% in the visible range.

Abstract: The Ga-doped ZnO (GZO) films were prepared by DC magnetron sputtering at different substrate temperature, followed by etching in 0.5%HCL solution for 15s to obtain textured surface. Optical and electrical properties, structural and surface morphology of thin films were investigated. The results indicated that the transmittance rate decreased and the C-axis preferred orientation of films enhanced with the increase of the substrate temperature. When temperature increased from room time (RT) to 200°C, the resistivity decreased and the quality crystal became better, while substrate temperature above 250°C, the resistivity increased,the deterioration of crystallinity emerged. For the textured film deposited at 200°C, it obtained the minimum resistivity of 0.84×10^-3/(Ω•cm) and had a good light trapping ability.

Abstract: Amorphous Silicon-germanium films were prepared by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) on glass substrates. The structural characteristics, deposition rate, photosensitivity, and optical band gap of the silicon-germanium thin films were investigated with plasma power varying from 15W to 45W. The deposition rate increased within a certain range of plasma power. With the plasma power increasing, the photosensitivity of the thin films decreased. It is evident that varying the plasma power changes the deposition rate, photosensitivity, which was fundamentally crucial for the fabrication of a-Si/a-SiGe/a-SiGe stacked solar cells. For our deposition system, the most optimization value was 30-35W.

Abstract: The SiC thin films as the window layer was prepared by PECVD technology in this article, investigated the influence of hydrogen dilution on the optical and micro-structural properties of SiC thin films, Analyzed optical band-gap，deposition rate and surface morphology under different hydrogen dilution ratio, found the optimal growth craft under the same conditions. The results showed that the optical band-gap of the window layer achieved the widest 2.2ev when hydrogen dilution rate was 6.25.

Abstract: The ZnO films were deposited on quartz glass substrate by RF magnetron sputtering. The influences of the deposition power, the Ar/O2 ratio and the total press on the crystallinity of ZnO films were analyzed by X-ray diffraction. The results show that the films deposited at Ar/O2 ratio of 2:3 have better crystalline quality under our experimental conditions. The optimum power is about 120-160 W. The crystal structure was significantly influenced by the total pressure in the chamber. The total press should below 1 Pa in order to get high quality ZnO films.

Abstract: The SiC thin films as the window layer of p-i-n solar cell was prepared by PECVD technology in this article,investigated the influence of hydrogen dilution on the structure and optical properties of SiC thin films,found the optimal growth craft under the same conditions. The results showed that the optical band-gap of the window layer achieved the widest 2.2ev when hydrogen dilution rate was 6.25, furthermore, got inerratic surface morphology with deposition rate up to 0.1nm / s.

Abstract: The ZnO films were deposited on quartz glass substrate by RF magnetron sputtering. The ZnO films are highly c-axis oriented with the (002) plane parallel to the substrate. The grains size estimated by the XRD diffraction rises with increase in the Ar/O2 ratio. The optical absorption edge and the near absorption edge characteristics of ZnO films have also been investigated. The optical band gaps of the films have been evaluated from the absorption coefficient of ZnO films. It is found that the value of the optical band gap varys from 3.26 eV to 3.32 eV due to the energy gap enhancement induced by quantum confinement. This variation of band gap can be explained with the theory developed by Brus. For all the films, the absorption coefficient shows the Urbach exponential dependence in the near band edge regime. It is also observed that the value E0 decreases with the Ar/O2 ratio increasing.

Abstract: The ZnO films were deposited on Si substrate by radio frequency (RF) magnetron sputtering. The effects of the Ar/O2 ratios on the structural characteristics and the internal stress in the ZnO films have been studied. The SEM images shows that the ZnO grains are nano-sized and tightly packed. The ZnO films are highly c-axis oriented with the (002) plane parallel to the substrate. The samples has a stress of the order of 1.0 × 1010 dyn/cm2. It is found that the size of ZnO crystal grains distinctly depends on the stress in the ZnO films. In order to deposite ZnO films with good crystalline quality, the stress caused by the growth process can be depressed by adjusting the Ar/O2 ratios.