Deep levels at p-n and n-p AlGaAs-GaAs heterojunction interfaces

Forward current-voltage measurements and DLTS spectra were obtained for p^--n and n^--p Al0.3Ga0.7As-GaAs heterodiodes. The current-voltage measurements support a tunneling current model for the p^--n diodes and a diffusion-recombination current model for the n^--p diodes. No deep levels were observed for the p^--n structure, but two new levels at about 0.1 and 0.4 eV below the conduction band edge, and possibly zinc related, were found in the n^--p devices.