Preparation And Physical Properties Of ZnSnN₂ Thin Films

ZnSnN₂ is a new type of three element compound semiconductor used in thin film solar cell materials. Compared with other compound thin film solar cell materials, ZnSnN₂ has the advantage of low cost of raw materials and non-toxic, very suitable for mass production. However, the reported ZnSnN₂ films were prepared on expensive substrates with heating, which leads to the increase in the cost and energy consumption. In addition, ZnSnN₂ on the optical properties of ZnSnN₂ were and electrical properties reported very little, there is no research on the physical properties.In this work, amount of experiments were carried out in order to reduce the fabricated temperature and the requirements of the substrates, meanwhile the optical and electrical properties are systematically investigated.（1） Polycrystalline thin films with single ZnSnN₂ phase were fabricated by magnetron sputtering at room temperature. The substrates include quartz, Si, glass and PET. The influences of process parameters on the crystal structures of ZnSnN₂ thin films were systematically investigated. And the optimizing process parameter for preparing single-phase ZnSnN₂ thin films we obtained.（2）The optical properties of the ZnSnN₂ films were sutudied by ellipsometry and ultraviolet visible spectrophotometer. The optical parameters such as the refractive index, absorption coefficient, bandgap and transparency were obtained by the method of Lorentz model. The easy-fabricated ZnSnN₂ possesses a sound absorption coefficient comparable to some typical photovoltaic materials such as Ga As, Cd Te.（3）The electrical properties of the ZnSnN₂ films were studied and verified by the fabrication and investigation of their thin- film transistors. The obtained ZnSnN₂ films showed n-type conductivity with the electron concentration in a rage of 1017¹019cm-3 and the largest mobility of 8.1 cm2/V·s.