Mixed Dimensional Te Nanowire-Te Nanosheet Heterojunctions with 2D Electron Gas on SrTiO3for Diode Applications

Abstract

Two-dimensional (2D) tellurium (Te) has drawn extensive interest for its intriguing properties, such as p-type conduction, high mobility, environmental stability, and field effects. Here, we employ a substrate-free solution method to prepare quasi-1D Te nanowires (TNWs) and 2D Te nanosheets (TNSes) to construct van der Waals heterojunctions with two-dimensional electron gas (2DEG) on SrTiO3 (STO). Such heterojunctions exhibit good rectifying behavior, indicating promising applications as diodes. The ratios of positive and negative currents reach as high as 103 for TNW/2DEG-STO and 107 for TNS/2DEG-STO. Such diodes show strong suffertibility to large negative voltages up to -100 V. Their high performances are found to cover a broad temperature range. In addition, the forward current of the TNW/2DEG-STO heterojunction shows a temperature dependence different from that of the TNS/2DEG-STO heterojunction. A main explanation is that the TNWs are more influenced by the edge effect than the TNSes, supported by electric force microscopy.