OBSERVATION OF ELECTRON-EMISSION FROM THE ISOTYPE HETEROINTERFACE BY DLTS

With C-V measurements and DLTS the heterointerface of a Schottky contact/n-GaAs/n-GaAlAs-structure was analyzed. A DLTS signal was found, which was identified as due to electron emission from the potential well at the heterojunction. The theoretical treatment of the electron emission and capture from the quantum well indicates some peculiarities, which could be confirmed experimentally. First, the DLTS peak can be of positive or negative sign in dependence on the density of the two-dimensional electron gas at the interface. Second, the barrier energies for the emission and capture of electrons by the well are essentially the same. Finally, it can be detected only in a certain range of a reverse bias voltage and of a filling pulse amplitudes. © 1990.