Direct observation and manipulation of hot electrons at room temperature

Abstract

In modern electronics and optoelectronics, hot electron behaviors are highly concerned since they determine the performance limit of a device or system, like the associated thermal or power constraint of chips, the Shockley-Queisser limit for solar cell efficiency. Up-to-date, however, the manipulation of hot electrons is mostly based on conceptual interpretations rather than a direct observation. The problem arises from a fundamental fact that energy-differential electrons are mixed up in real-space, making it hard to distinguish them from each other by standard measurements. Here we demonstrate a distinct approach to artificially (spatially) separate hot electrons from cold ones in semiconductor nanowire transistors, which thus offers a unique opportunity to observe and modulate electron occupied state, energy, mobility, and even its path. Such a process is accomplished through the scanning-photocurrent-microscopy (SPCM) measurements by activating the intervalley-scattering events and one-dimensional charge-neutrality rule. Findings discovered here may provide a new degree of freedom in manipulating nonequilibrium electrons for both electronic and optoelectronic applications.

Low‐Noise Dual‐Band Polarimetric Image Sensor Based on 1D Bi2S3 Nanowire

“…α H ( f = 1 Hz) of the as‐synthesized Bi 2 S 3 NWs was estimated to be ≈2 × 10 −5 , considering that α H is affected by surface defects, the low value of α H observed in the Bi 2 S 3 NWs can be attributed to the lack of surface defects. [ 49,50 ] Obviously, the value of α H is better than most reported 1D materials‐based devices. The reported performance of Bi 2 S 3 ‐based photodetectors synthesized via different approaches and some other nanostructure‐based photodetectors are summarized in Table 2 .…”

“…Defects act as carrier traps play an important role in tailoring the optoelectronic properties of materials and adjusting 1/f noise, which is consistent with the previous report. [28,49,50] In this work, the sulfur-assisted vapor transport preparation method reduces S vacancies of the Bi 2 S 3 NWs, increasing optoelectronic performances while reducing 1/f noise. The combination of superior photoresponse properties and lower electrical noise in Bi 2 S 3 NWs provides excellent material and device platform for polarized imaging application.…”

Artificial Synapse Based on an InAs Nanowire Field-Effect Transistor with Ferroelectric Polymer P(VDF-TrFE) Passivation

“…Previous reports have shown that the light-induced photogating effect or hot-electron storing effect occurring at different surface energy levels of InAs NWs can alter the carrier relaxation process and endow them with sufficiently long lifetimes. , Also, charge trapping and detrapping at the interface between the native oxide layer of InAs NW and high- k dielectric Al 2 O 3 have been reported to endow the device with multiple memory states, enabling the emulation of the synaptic behavior . To understand the mechanism of the P­(VDF-TrFE)-coated InAs NW synaptic transistors, we also study the synaptic properties of the pristine device (as shown in Figure S7a,c) and compare them with those after the P­(VDF-TrFE) coating (as shown in Figure S7b,d).…”

Fast near-infrared photodetectors from p-type SnSe nanoribbons

“…NRs possess distinct and unique physical properties compared to two-dimensional or other dimensional counterparts have been demonstrated [1][2][3]. Due to the adjustable length, width, thickness of the synthesized NRs, resulting in the unique transport mechanisms of photons and electrons [4][5][6][7].…”