OPTICAL CHARACTERIZATION OF TiO_2 THIN FILM ON SILICON SUBSTRATE DEPOSITED BY DC REACTIVE MAGNETRON SPUTTERING

TiO2 thin film has attracted considerable attention in recent years, due to its different refractive index and transparency with amorphous and different crysta ls in the visible and near-infrared wavelength region, high dielectric constant, wide band gap, high wear resistance and stability, etc, for which make it being used in many fields. This paper aims to investigate the optical characterizatio n of thin film TiO2 on silicon wafer. The TiO2 thin films were prepared by DC re active magnetron sputtering process from Ti target. The reflectivity of the film s was measured by UV-3101PC, and the index of refraction (n) and extinction coef ficient (k) were measured by n & k Analyzer 1200.

PREPARATION AND CHARACTERIZATION OF POLY-CRYSTALLINE SILICON THIN FILM

Poly-crystalline silicon thin film has big potential of reducing the cost of solar cells. In this paper the preparation of thin film is introduced, and then the morphology of poly-crystalline thin film, is discussed. On the film we developed poly-crystalline silicon thin film solar cells with efficiency up to 6.05% without anti-reflection coating.

THE BAND STRUCTURE AND WORK FUNCTION OF TRANSPARENT CONDUCTING ALUMINUM AND MANGANESE CO-DOPED ZINC OXIDE FILMS

Al and Mn co-doped-ZnO films have been prepared at room temperature by DC reacti ve magnetron sputtering technique. The optical absorption coefficient, apparent and fundamental band gap, and work function of the films have been investigated using optical spectroscopy, band structure analyses and ultraviolet photoelectro n spectroscopy (UPS). ZnO films have direct allowed transition band structure, w hich has been confirmed by the character of the optical absorption coefficient. The apparent band gap has been found directly proportional to N2/3, showing that the effect of Burstein-Moss shift on the band gap variations dominates over the many-body effect. With only standard cleaning protocols, the work function of ZnO: (Al, Mn) and ZnO: Al films have been measured to be 4.26 and 4.21eV, respec tively. The incorporation of Mn element into the matrix of ZnO, as a relatively deep donor, can remove some electrons from the conduction band and deplete the d ensity of occupied states at the Fermi energy, which causes a loss in measured p hotoemission intensity and an increase in the surface work function. Based on th e band gap and work function results, the energy band diagram of the ZnO: (Al, M n) film near its surface is also given.

OBSERVATION ON DEFECTS IN POLYCRYSTALLINE SILICON THIN FILMS

Polycrystalline silicon thin films were prepared by RTCVD (rapid thermal chemica l vapor deposition) method on several substrates such as SSP (silicon sheet from powder) ribbon, poly-Si wafer and mono-Si wafer. Intra-granular defects such as stacking faults, twins and microstructure defects were investigated on thin fil ms by scan electron microscopy (SEM) technique.

STRUCTURE, MECHANICAL PROPERTIES AND THERMAL STABILITY OF DIAMOND-LIKE CARBON FILMS PREPARED BY ARC ION PLATING

Diamond-like Carbon (DLC) films have been prepared on Si(100) substrates by arc ion plating in conjunction with pulse bias voltage under H2 atmosphere. The depo sited films have been characterized by scanning electron microscopy and atomic f orce microscopy. The results show that the surface of the film is smooth and den se without any cracks, and the surface roughness is low. The bonding characteris tic of the films has been studied by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. It shows the sp3 bond content of the film deposited at -200V is 26.7%. The hardness and elastic modulus of the film determined by nanoindent ation technique are 30.8 and 250.1GPa, respectively. The tribological characteri stic of the films reveals that they have low friction coefficient and good wear- resistance. After deposition, the films have been annealed in the range of 350-7 00℃ for 1h in vacuum to investigate the thermal stability. Raman spectra indica te that the ID/IG ratio and G peak position have few detectable changes below 50 0℃. Further increasing the annealing temperature, the hydrogen can be released, the structure rearranges, and the phase transition of sp3 configured carbon to sp2 configured carbon appears.