Interfacial traps in Ga0.47In0.53As/InP heterostructures

Abstract

This paper reports on a study of n-type GaInAs layers grown by molecular-beam epitaxy on semi-insulating Fe-doped InP substrates. Hall measurements are performed on bevelled layers to obtain carrier concentration and mobility profiles. An infrared transient spectroscopy technique (backgating effect induced by infrared illumination in the 0.8–2 μm wavelength range) is used to detect the deep level responsible for the reduction of both carrier concentration and mobility near the heterointerface. An electronlike trap with an activation energy of ≊0.32 eV is found. Optical ionization and neutralization energies are also obtained. The results are compared with those obtained by others from electron paramagnetic resonance, photoconductivity, and deep level transient spectroscopy measurements. It is concluded that the electronlike trap, tentatively ascribed to an Fe acceptor level, is located at the heterointerface.