Observation of negative differential resistance from a single barrier heterostructure

Abstract

We report the first experimental observation of negative differential resistance (NDR) due to electron tunneling in a single barrier heterostructure. The largest peak-to-valley current ratio attained is slightly greater than 2:1. The single barrier structure studied here consists of a thin CdTe layer sandwiched between two Hg0.78Cd0.22Te electrodes. In this particular material system, NDR can only be achieved at low temperatures (T=4.2 K) due to the dominance of thermionic hole currents at high temperatures. The observation of NDR in this system suggests that the low-temperature valence-band discontinuity at the HgTe-CdTe interface is small (less than 100 mV). Room-temperature operation of single barrier NDR structures may be possible in other semiconductor systems.