Determination of valence and conduction-band discontinuities at the (Ga,In) P/GaAs heterojunction by <i>C</i>-<i>V</i> profiling

TLDR

The study profiles both p‑p and n‑n (Ga,In)P/GaAs heterojunctions to independently determine the valence‑band and conduction‑band discontinuities. Capacitance‑voltage profiling combined with computer reconstruction of the C‑V curves was employed to verify data consistency. The C‑V profiling revealed a straddling band alignment with ΔEv = 0.24 eV and ΔEc = 0.22 eV (±10 meV), and suggests that the (Ga,In)P/(Al,Ga)As system becomes staggered at certain Al compositions.

Abstract

The valence and conduction band discontinuities for the lattice matched (Ga,In)P/GaAs heterojunction have been determined by capacitance-voltage (C-V) profiling. Both p-p and n-n heterojunctions were profiled, in order to obtain separate and independent values for both the valence-band-edge discontinuity (ΔEv) and the conduction-band discontinuity (ΔEc). The band lineup is found to be of the straddling type with the valence- and conduction-band discontinuities 0.24 and 0.22 eV, respectively, with an estimated accuracy of ±10 meV. Computer reconstruction of the C-V profiles was used to check the consistency of the data. The band offset data indicate that the (Ga,In)P/(Al,Ga)As system should be staggered for a certain range of Al compositions.