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

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.

Sustained Resistive Switching in a Single Cu:7,7,8,8-tetracyanoquinodimethane Nanowire: A Promising Material for Resistive Random Access Memory

“…1(b,c). There is an essential difference that this SNW device shows from that of previously reported devices11121316,18. The devices reported here show unipolar switching in contrast to bipolar switching reported in all past reports.…”

“…Both types of devices studied showed unipolar switching in contrast to past reports that showed bi-polar RSS. There are some reports on RSS in a SNW of Cu:TCNQ1217 connected between two Au electrodes. Zheng el al 17.…”

“…Past investigations indicated the role of contact on bipolar switching observed in planar devices made on Cu:TCNQ films. These investigations also localized the cause of switching near the contacts1316,18. However, the role of contact that has been discussed in past studies is qualitative in nature and no quantitative model based analysis was done which allows evaluation of actual changes in contacts as well as that in the body of the NW.…”

Light Induced Electron-Phonon Scattering Mediated Resistive Switching in Nanostructured Nb Thin Film Superconductor

“…In order to understand the mechanisms behind the observed NPC, different explanations like surface plasmon resonance (SPR) 6 , electron-surface plasmon polaritons (SPPs) scattering and the related Joule heating effect at the grain boundaries 17 , hot electrons trapping 18 , energy gap opening 16 and trap level due to defects etc. are addressed in the literature.…”

The way to high-performance single nanowire photodetectors: problems and prospects

“…Interestingly, the NW photodetectors designed by Guo et al are exactly based on this regime. For these InAs NWs showing NPC, surface defects act as a photogating layer trapping hot electrons whereas photogenerated holes remain in the NW core and recombine with free electrons [5,6]. These core/shell-like NWs could achieve ultrahigh negative photoconductive gain of~10 5 .…”