Tingzhi Liu

Influence of different pH regulators and pH values on optical properties of ZnS nanocrystalline thin films

ZnS thin films were prepared under different pH regulators and pH values by the chemical bath deposition method (CBD). Deposition mechanism was discussed and optical properties of ZnS thin films were measured by n k d- film analysis system. Results show the addition of pH regulators is beneficial to decrease the precipitation of the solution. The decrease of the precipitation of the solution could increase the deposition rate of the film. When there is addition of NH3 and the controlled pH value is 10.9 in the solution, the deposition rate of the film is largest, which is agreement with the discussed condition that when there is no pH regulator and the pH value is dropped to 10.9 in the solution. Band edge of the transmission of all films shifts greatly to short wavelength and tends to be similar. Band gap values of all the films are larger than 4.00eV. Grain size of all the thin films is almost 5nm and the films have the pronounced quantum size effect. It shows that it is easy for ZnS to form a lot of nucleation points on the substrate, but difficult to grow up because of the existence of intermolecular hydrogen bond effect in the solution.

Zinc Oxide Thin Films Grown by RF Magnetron Sputtering on Nanostructure Al Thin Layer/Glass and Glass Substrates

ZnO films with random and highly (002)-preferred orientation were deposited on nanostructured Al (n-Al) /glass and glass substrates at room temperature by RF magnetron sputtering method, respectively. According to I (002)/I (100) ≈I annealed (002)/I annealed (100) ≈1.1 (on n-Al) and 2I annealed (002) /I (002) (on n-Al) ≈ I annealed (002) /I (002) (on glass) ≈3.1, the rough n-Al surface is suitable for the growth of a-axis orientation, and the appearance of the (100) peak plays a major role in decreasing the c-axis orientation. The average optical transmission of the film on n-Al layer increased significantly after annealing. At the same time, the growth mode and E g of ZnO films were discussed. On n-Al layer/glass substrate, it is not easy for the growth interface to form the smooth surface during the deposition process and Stranski Krstanov plays a primary role on the deposition of the films. Due to the significant increase of the interplanar spacing d (101), the band gaps for as-grown and annealed films grown on n-Al decreased, comparing with that of the film deposited on glass substrate.