Energy distribution of gap states in hydrogenated amorphous silicon by post-transit photocurrent spectroscopy: Validity of an indium-tin oxide/ silicon oxide double-layer gate.

Reduction of junction leakage currents is important to exactly obtain the energy distribution of gap states in hydrogenated amorphous silicon (a-Si:H) by post-transit photocurrent spectroscopy (PTPS). A double-layer transparent conducting gate composed of indium-tin-oxide (ITO) and silicon oxide (SiOx) is an effective means for this purpose in Schottky barrier sSBd diodes. However, there has been some concern that the presence of the SiOx layer could affect the PTPS results. We demonstrate from careful experimental studies that the insertion of the SiOx layer between ITO and a-Si:H does not give any additional structure in the energy distribution of gap states of a-Si:H measured by PTPS and the SB diodes with the ITO-SiOx double-layer gate are suited for exact PTPS measurements. [ABSTRACT FROM AUTHOR]