The Effectiveness of Ga Percent on the Electrical Characteristics of Al/CuIn1-xGaxSe2/ITO Schottky Junctions

Abstract

The electrodeposition method has been employed to deposit our quaternary semiconductor thin films CuIn_1-xGa_xSe₂ (CIGS) which is deposited on Indium Tin Oxide (ITO) substrates with different Gallium ratios (x=0, 0.2, 0.4, 0.6, 0.8 and 1). The structural and optical characteristics variation of the films with altering Ga percent has been studied. The impact of changing the Ga/(In+Ga) atomic ratio on the electrical transport characteristics of electrodeposited CIGS thin films has been investigated using I-V and C-V measurements. All junctions have revealed the Schottky behavior. The energy gap of the studied compositions has increased with increasing Ga content. This lowered the values of charge mobility in the investigated films. Besides, the optimum Ga/(In+Ga) atomic proportion in the view of the obtained results is achieved by adding Ga with 20 %. Also, this finding approves the validation of our proposed criterion in expecting the most efficient photovoltaic junctions. The obtained results could improve our current knowledge of the quaternary photovoltaic solar cells.