Effect of photoexcitation on the surface band bending in δ‐doped GaAs:Si/Al_0.33Ga_0.67As double heterostructures Available to Purchase

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 δ‐doped GaAs:Si/Al_0.33Ga_0.67As 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 δ‐doping layer with photogenerated holes localized at the topmost heterointerface. For the highest power densities of ≂10³ W/cm² the electric field at that interface becomes almost zero indicating that band bending due to surface trap states is essentially removed.