Three Midgap Levels in LEC n-GaAs Determined by DLTS Using Au and Al Schottky Barrier Diodes

Abstract
Midgap levels in n-GaAs have been studied in detail by DLTS and capacitance transient analysis using Au and Al Schottky barrier contacts. In addition to EL2, which we call EO1 here, two other midgap levels, EO2 and EO3, were observed. The variations of EO1 and EO2 concentrations did not correlate with the distribution of the optical absorption coefficient in a wafer, while that of the EO3 concentration exhibited good correlation. This suggests that EO3 is identical or related to the optically detected midgap level.