Photoreflectance and differential surface photovoltage studies of δ-doped GaAs/AlAs multiple quantum wells

Bronislovas Čechavičius, Julius Kavaliauskas, Genè Krivaitè, Dalius Seliuta, Gintaras Valušis, Matthew P. Halsall, Matthew J. Steer, Paul Harrison

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


We measured the photoreflectance (PR) and wavelength-modulated differential surface photovoltage (DSPV) spectra of δ-doped GaAs/AlAs multiple quantum wells (MQW) with different well widths and doping levels. We demonstrated that PR and DSPV are powerful contactless tools for the characterization of MQW structures. We observed Franz-Keldysh oscillations in the PR spectra, which enabled us to determine the built-in electric fields in the GaAs/AlAs MQW structures. As it turned out, in the GaAs buffer/cap layers the field strength is in the range of 18-20 kV/cm. It was found that a buried interface rather than the structure surface very probably governs the SPY effect. Sharp features associated with excitonic optical transitions were revealed in both, PR and DSPV spectra. From the line shape analysis of the modulation spectra, we estimated optical transition energies and broadening parameters. The energy levels and interband transition energies calculated by the transfer matrix method are in good agreement with the experimental values. The influence of the doping on the broadening of exciton resonances was observed and investigated. δ-doped GaAs/AlAs quantum wells, photoreflectance, surface photovoltage, differential surface photovoltage.

Original languageEnglish
Title of host publicationOptical Materials And Applications
EditorsArnold Rosental
Number of pages8
ISBN (Print)9780819459534
Publication statusPublished - 13 Jun 2006
Externally publishedYes
EventOptical Materials and Applications - Tartu, Estonia
Duration: 1 Aug 20053 Aug 2005

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptical Materials and Applications


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