Preparation of CuInSe2 by e-beam ablation technology and properties of thin films - solar cell components

We used a new technological method of pulsed electron beam (e-beam) ablation to prepare high quality CuInSe₂ (CIS) thin films. This method is analogous to pulsed UV-laser ablation but costs significantly lower. In this method, the CIS deposition was made by pulsed, high current, and magnetically self pinched electron beam produced in a low pressure channel spark camera at the following conditions: high voltage of 10-20 kV, pulse duration of 100 ns, repetition rate of 1-5 Hz, power density <500 MW/cm², argon pressure of 1-3 Pa, substrate temperatures of 250-550°C. CIS thin films are found to have a strong preferential (112) orientation, the chalcopyrite structure, columnar grain microstructure, and specular surface consisting of a smooth background of closely arranged grains as well as precipitates, and spherical particles disposed on the film surface. The Cu/In ratio in the films was found to be temperature dependent and in the range of 0.9-1.2. A well-defined absorption edge near the band gap with the energy gap of Eg=0.99 eV was observed for CIS films. Selenium doping procedure of the In-rich thin films deposited at T_sub=250°C were made to improve the microstructure of these films