Determination of heterojunction band offsets by capacitance-voltage profiling through nonabrupt isotype heterojunctions

Abstract

It is shown that the capacitance-voltage (C-V) profiling technique to obtain heterojunction (HJ) band offsets is grading independent, that is, the band offset values obtained by it are the values for the limit of zero compositional grading, even in nonabrupt junctions. The result explains the good agreement of old data taken on nonabrupt HJ’s grown by liquid phase epitaxy (LPE) with more recent data on abrupt junctions. It suggests that LPE grown HJ’s may be used more freely than was previously thought to determine those offsets, making C-V profiling the most versatile technique for the determination of HJ band offsets.