INTERFACIAL PROPERTIES OF ZNSE GAAS HETEROVALENT INTERFACES/

The donor- and acceptor-like levels at ZnSe/GaAs heterovalent interfac es with different interfacial bonding configurations have been observe d by photoluminescence, and electric fields at the interfaces have bee n detected by photovoltage measurements. The most striking feature is the appearance of a new band near 1.405 eV, followed by several replic as due to LO phonons at energy 33 meV. This band is only present in sa mples of ZnSe grown on Zn-treated As-rich GaAs surfaces and we tentati vely attribute the peak to a free electron-acceptor recombination. The PL spectra from an Se-treated Ga-rich sample shows two dominant emiss ions at 1.45 and 1.46 eV which may be related to donor-like levels at the interface, and have been observed for the first time in our sample s. Photovoltage measurements show that the electric field at the inter face is quite large in a Zn-treated As-rich sample but is small in a S e-treated Ga-rich sample; this means the electric charges at the inter face of ZnSe/GaAs are different for these two kinds of samples. (C) 19 98 Published by Elsevier Science B.V. All rights reserved.