Formation of Zn-doped CuInSe2 films by thermal annealing using dimethylzinc

Copper indium diselenide (CuInSe2:CIS) pn-homojunction diodes were fabricated by the thermal diffusion of Zn into the p-type CIS films at 300 °C for 5 min using a dimethylzinc [(CH3)2Zn:DMZn] vapor. This method does not require any additional processing equipment since the diffusion can be carried out subsequent to the selenization of a Cu–In precursor using organoselenium liquid, such as diethylselenide [(C2H5)2Se:DESe]. A donor-to-acceptor pair emission attributable to Zn impurity was observed in the low-temperature photoluminescence spectrum. From the capacitance–voltage characteristics, the depletion layer width and diffusion potential of the junction were estimated as 300 nm and 0.6–0.7 V, respectively. The method is highly advantageous for the development of low-cost solar modules.