Carrier trapping in diamond Schottky barrier diode

Abstract

Carrier trapping in a diamond Schottky barrier diode, consisting of a stack of a p− drift and p+ contact layer, is experimentally studied via subgap photocurrent measurements. In the measurements, trapped carriers are detected as an increment of the diode current under a probe light illumination in a near infrared range of 2.0 μm (0.62 eV). The density of trapped carriers is examined, and it is found to be sufficiently low, compared with that of free carriers, by an order of 105. Interestingly, the trapped carriers are observed only for the forward bias of the diode; they are not observed for the reverse bias. This suggests that the carrier trapping, yielding trapped carriers, originates from the valence band offset at the p−/p+ interface.