ACTA

Optical and Terahertz Characterization of Be-Doped GaAs/AlAs Multiple Quantum Wells

B. Čechavičius^a, J. Kavaliauskas^a, G. Krivaitė^a, D. Seliuta^a, E. Širmulis^a, J. Devenson^a, G. Valušis^a, B. Sherliker^b, M.P. Halsall^b, M.J. Steer^c and P. Harrison^d
^a Semiconductor Physics Institute, A. Goštauto 11, 01108, Vilnius, Lithuania
^b Department of Physics, UMIST, Manchester M60 1QD, United Kingdom
^c Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom
^d IMP, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom

Full Text PDF

Received: 22 08 2004;

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.

DOI: 10.12693/APhysPolA.107.328
PACS numbers:78.66.-w, 85.30.De