Engineered interface properties in ZnSSe/GaAs heterovalent heterostructures

We investigate the interface properties of ZnSSe/GaAs heterovalent heterost ructures, using pn heterojunction diodes. It is found that only when Ga-S b onds are formed at the interface, the current-voltage I-V characteristic ex hibits a negative differential resistance (NDR). The photoresponse of the I -V characteristic suggests that the NDR originates from electron capture to an interface states band related to the Ga-S bonds. The presence of the in terface states is also proved by a deep-level transient spectroscopy. (C) 2 000 Elsevier Science B.V. All rights reserved.