Observation of Type I/II Transition in GaAs/InGaP Heterostructure by C-V Profiling

TL;DR

This study reports the first experimental observation of a type I/II band alignment transition in GaAs/InGaP heterostructures, caused by InGaP alloy ordering, using capacitance-voltage profiling at room temperature.

Contribution

It provides experimental evidence of the type I/II transition induced by alloy ordering in GaAs/InGaP heterostructures, previously predicted theoretically.

Findings

Observation of type I/II transition via C-V profiling

Correlation between alloy ordering and band alignment change

First experimental demonstration of this transition in GaAs/InGaP

Abstract

It is known in the literature that InGaP alloy synthesized within a certain range of growth temperature (520 - 720 degree Centrigrade) shows Cu-Pt crystal ordering. This ordering reduces the band gap energy . It was predicted that the ordering induced modification of energy levels of InGaP lowers its conduction band edge, which could change a type I band alignment at a GaAs/InGaP heterojunction to type II . Here we report the first observation of this ordering related type I/II transition for a GaAs/InGaP heterojunction by C-V profiling experiments done at room temperature .