HgTe-CdTe double barrier tunneling structures

Abstract

Double barrier heterostructures consisting of HgTe-CdTe-HgTe-CdTe-HgTe layers are proposed as providing improved negative differential resistance current-voltage characteristics as compared with similar devices based on the GaAs-GaAlAs system. The small HgTe-CdTe valence-band offset and the inverted light holelike conduction band of HgTe produce intrinsic interface states with long decay lengths in the CdTe barrier layers. This enhances the transmission coefficient and thus the tunneling current. Also, the small offset causes the CdTe barriers to present more blockage to unwanted thermal electron currents than do typical GaAlAs barriers. The high mobility of HgTe reduces the series resistance of the contacting layers, thus reducing the bias voltage required to achieve resonance and increasing the speed of the device. The effectiveness of the structure will depend on the value of the valence-band offset and material quality.