Bulg. J. Phys. vol.33 no.s3 (2006), pp. 217-222

Surface Photovoltage Spectroscopy of GaAs Quantum Wells Embedded in AlAs/GaAs Superlattices

Ts. Ivanov, K. Kirilov, V. Donchev, K. Germanova
University of Sofia, Faculty of Physics, 5 James Bourchier Blvd., BG-1164 Sofia, Bulgaria
Abstract. We have studied GaAs quantum wells (QWs) embedded in (AlAs)4/(GaAs)8 superlattices (SLs) by means of surface photovoltage (SPV) spectroscopy, taking advantage of its high sensitivity and contactless measurements. The metal-insulator-semiconductor (MIS) operation mode of the SPV method is applied. The SPV spectra, recorded at low frequencies, clearly reveal spectral structures corresponding to: i) electron-to-heavy hole (E-HH) and electron-to-light hole (E-LH) exciton transitions in the two GaAs QWs, ii) E-HH transitions in the SL and iii) mixed E(SL) - HH(QW) transitions. Their energy positions correspond well to our electronic structure calculations performed by means of the envelope function approximation, as well as to photoluminescence data measured previously in the same and similar samples.

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