Hot Carrier Trapping Induced Negative Photoconductance in InAs Nanowires toward Novel Nonvolatile Memory

TL;DR

This paper introduces a new negative photoconductivity mechanism in InAs nanowires caused by hot electron trapping, enabling a reversible, light-controlled memory device with potential applications in low-power optoelectronics.

Contribution

It reports a novel hot carrier trapping induced negative photoconductance in InAs nanowires, leading to a reversible, light- and gate-controlled nonvolatile memory device.

Findings

Significant suppression of conductivity under illumination with a gain up to 10^5.

Temperature-dependent recovery indicating thermally activated detrapping.

Reversible memory operation at low temperatures with quenched conductance recovery.

Abstract

We report a novel negative photoconductivity (NPC) mechanism in n-type indium arsenide nanowires (NWs). Photoexcitation significantly suppresses the conductivity with a gain up to 10^5. The origin of NPC is attributed to the depletion of conduction channels by light assisted hot electron trapping, supported by gate voltage threshold shift and wavelength dependent photoconductance measurements. Scanning photocurrent microscopy excludes the possibility that NPC originates from the NW/metal contacts and reveals a competing positive photoconductivity. The conductivity recovery after illumination substantially slows down at low temperature, indicating a thermally activated detrapping mechanism. At 78 K, the spontaneous recovery of the conductance is completely quenched, resulting in a reversible memory device which can be switched by light and gate voltage pulses. The novel NPC based optoelectronics may find exciting applications in photodetection and nonvolatile memory with low power consumption.