Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524


Published online November 15, 2007

Copyright © The Korean Physical Society.

Photoreflectance Interference in Modulation-Doped AlGaAs/GaAs Single Heterojunctions

Kyu-Seok Lee, W. S. Han, J. O. Kim, S. J. Lee and S. K. Noh

J. Korean Phys. Soc. 51(5), 1821 - 1824 (2007)


We report on the photoreflectance (PR) interference in an $n$-modulation-doped AlGaAs/GaAs single heterojunction grown on a semi-insulating GaAs substrate. An oscillatory feature is observed in the spectral region below the bandgap of GaAs and is attributed to the interference of two light beams, one reflected from the AlGaAs/GaAs interface and the other from the upper boundary of the hole-accumulating GaAs. The modulation of the refractive index of GaAs at the hole-accumulation region with the modulation light beam gives rise to the interference effect. Analyzing theoretically the observed oscillatory feature with a single homo-interface model consisting of intrinsic GaAs and hole-accumulating GaAs, we determined the thickness of the intrinsic GaAs.

Keywords: Photoreflectance, Interference, AlGaAs/GaAs single heterojunction