We report on optical, photoreflectance and surface photovoltage, as well as terahertz photocurrent investigation of Be-doped GaAs/AlAs multiple quantum wells at room and liquid helium temperatures, respectively. From the Franz-Keldysh oscillations observed in photoreflectance spectra we determine built-in electric fields within the structure. Interband transition energies calculated by the transfer matrix method are in qualitative agreement with experimentally determined values for the samples having various, from 2 × 1010 up to 2.5 × 1012 cm-2, Be doping densities. The photocurrent observed in the range of 5.4-7.3 THz we associate with photoionization of Be-acceptor states.
|Number of pages||5|
|Journal||Acta Physica Polonica A|
|Publication status||Published - 1 Feb 2005|
|Event||12th International Symposium on Ultrafast Phenomena in Semiconductors - Vilnius, Lithuania|
Duration: 22 Aug 2004 → 25 Aug 2004
Conference number: 12