Preparation Of Czts And ZnO Thin Films By Pulsed Laser Deposition

Cu2ZnSnS4(CZTS) is a kind of material with high potential to be used as the absorption laser of a thin film solar cell, which has many advantages such as high efficiency, abundant and low price supply of raw materials, and no pollution to the environment.In this thesis, pulsed laser deposition (PLD) was used to prepare CZTS and ZnO thin films under different conditions. Scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD) and ultraviolet-visible spectrophotometer were used to analyze the effect of processing parameters such as pulse laser energy and frequency, deposition time, annealing time, annealing temperature and environment atmosphere, on the surface topography, phase structure and photoelectric properties of the thin films. The main conclusions are drawn as follows:1. Well crystallized CZTS thin films were successfully prepared on ITO conductive glass substrates under the pulse laser energy of150mJ/p.2. The CZTS thin films show a strong (112) prefer orientation at the pulsed laser frequency of5Hz; While at other frequencies the prefer orientation tend to become (220).3. The quality of the film is associated with deposition time. When the deposition time was90min, the CZTS thin films are well crystallized, and the surface is smooth and dense.4. When the annealing time is60min, the surface of the CZTS thin film is dense and lack of defects. The surface roughness of the film decreases as the annealing time is prolonged, however, the surface impurities also increase gradually at the same time.5. After300℃annealing treatment, the CZTS thin films have good crystalline quality, less impurity defects and compact surface. The transmittance of the films is0.8%within the range of visible light, the forbidden bandwidth is1.521eV, and the resistivity is0.009Ω·cm. As annealing temperature increases, the film’s transmittance also increases, and forbidden bandwidth become wider.6. A state of rich in Sn is benefit for the CZTS thin film to grow along the [112] direction.7. Well crystallized and dense ZnO films with small surface roughness were prepared under the conditions of150mJ/p of laser energy,200℃of substrate temperature, and0.8Pa oxygen partial pressure. The films’transmittances are greater than85%.