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Surface photovoltage investigation of GaAs quantum wells

TS. IVANOV1,* , V. DONCHEV1, K. KIRILOV1, K. GERMANOVA1

Affiliation

  1. Faculty of Physics, Sofia University, 5, blvd. J.Bourchier, Sofia-1164, Bulgaria

Abstract

We have studied GaAs quantum wells (QWs) embedded in (AlAs)4/(GaAs)8 superlattices (SLs) with graded interfaces by means of surface photovoltage (SPV) spectroscopy, taking advantage of its high sensitivity and contactless measurements. The metal-insulator-semiconductor operation mode of the SPV method is applied. SPV spectral dependencies are measured at room temperature in samples containing one GaAs QW (5 nm) embedded between 20 and 26 periods of SL. The SPV amplitude spectrum, recorded at a light modulation frequency of 94 Hz, reveals peak structures, related to electron-to-heavy hole and electron-to-light hole exciton transitions in the GaAs QW and a step-like structure related to the optical transitions between the electron and hole SL mini-bands. Their energy positions correspond well to our electronic structure calculations performed by means of the envelope function approximation, considering a model Al concentration profile very close to the experimental one, as well as to photoluminescence data measured on similar samples. This investigation shows some of the SPV spectroscopy interesting abilities for characterization of complicated nanostructures..

Keywords

Surface Photo-voltage, Quantum well, Superlattice, Photoluminescence, Graded interface.

Submitted at: Nov. 1, 2006
Accepted at: Jan. 15, 2007

Citation

TS. IVANOV, V. DONCHEV, K. KIRILOV, K. GERMANOVA, Surface photovoltage investigation of GaAs quantum wells, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 1, pp. 190-193 (2007)