The Effect of Doping Ratios on Structure, Composition, and Electrical Properties of Absorber Formed by Thermal Sintering

Abstract

Chalcopyrite compounds of copper indium gallium diselenide (CIGS) absorber were fabricated by using binary-particle (Cu 2 Se, In 2 Se 3 , and Ga 2 Se 3 ) precursors with thermal sintering method. The binary-particle ink was firstly prepared by milling technology and then printed onto a soda lime glass substrate, which was baked at a low temperature to remove solvents and form a dry precursor. Following milling, the average particle size of agglomerated CIGS powder is smaller than 1.1 m. Crystallographic, stoichiometric, and electrical properties of precursor CIGS films with various doping amounts of Ga 2 Se 3 had been widely investigated by using thermal sintering in a nonvacuum environment without selenization. Analytical results reveal that the CIGS absorption layer prepared with a Ga 2 Se 3 doping ratio of 3 has a chalcopyrite structure and favorable composition. The mole ratio of Cu : In : Ga : Se of this sample was 1.03 : 0.49 : 0.54 : 1.94, and related ratios of Ga/(In + Ga) and Cu/(In + Ga) were 0.52 and 0.99, respectively. The resistivity and carrier concentration were 3.77 ohm-cm and 1.15 E + 18 cm −3 .