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Effect of photoexcitation on the surface band bending in delta-doped GaAs:Si/Al0.33Ga0.67As double heterostructures.

Einfluß von optischer Anregung auf die Oberflächen-Bandverbiegung in delta-dotierten GaAs:Si/Al0.33Ga0.67As Doppelheterostrukturen
: Richards, D.; Wagner, J.; Fischer, A.; Ploog, K.


Applied Physics Letters 61 (1992), Nr.22, S.2685-2687 : Abb.,Lit.
ISSN: 0003-6951
ISSN: 1077-3118
Fraunhofer IAF ()
III-V Halbleiter; Oberflächenbandverbiegung; optical spectroscopy; optische Spektroskopie; surface band bonding

Photoluminescence spectroscopy in combination with electric-field-induced Raman scattering have been used to study the effect of photoexcitation on the surface electric field due to surface trap states in Delta-doped GaAs:Si/Alsub0.33Gasub0.67As double heterostructures. Upon variation of the optical power density over four orders of magnitude a continuous reduction of the surface electric field is found for increasing cw illumination. This is evident from a decrease of the electric-field- induced Raman signal and from a high-energy shift of the photoluminescence due to recombination of electrons at the Delta-doping layer with photogenerated holes localized at the topmost heterointerface. For the highest power densities of approximately equal to 10high3 W/qcm the electric field at that interface becomes almost zero indicating that band bending due to surface trap states is essentially removed.