Slowing Hot-Electron Relaxation in Mix-Phase Nanowires for Hot-Carrier Photovoltaics

Abstract

Hot carrier harvest could save 30% energy loss in solar cells. So far, however, it is still unreachable as the photoexcited hot carriers are short-lived, ∼1 ps, determined by a rapid relaxation process, thus invalidating any reprocessing efforts. Here, we propose and demonstrate a feasible route to reserve hot electrons for efficient collection. It is accomplished by an intentional mix of cubic zinc-blend and hexagonal wurtzite phases in III−V semiconductor nanowires. Additional energy levels are then generated above the conduction band minimum, capturing and storing hot electrons before they cool down to the band edges. We also show the superiority of core/shell nanowire (radial heterostructure) in extracting hot electrons. The strategy disclosed here may offer a unique opportunity to modulate hot carriers for efficient solar energy harvest.

Optical Properties of Few-Layer Ti3CN MXene: From Experimental Observations to Theoretical Calculations

“…This could possibly be attributed to the large density of degenerative bands in the Ti 3 CNO 2 conduction band where the relaxation takes place. The thermal fluctuations break the degeneracy and create a complicated multilevel electronic structure, which is responsible for capturing and storing hot electrons before they cool down to the conduction band minimum …”

“…The thermal fluctuations break the degeneracy and create a complicated multilevel electronic structure, 43 which is responsible for capturing and storing hot electrons before they cool down to the conduction band minimum. 44 Nonlinear Optical Response. Motivated by the fact that NLO materials are of great importance for passive optical modulators and optical limiting devices, 45 we decided to investigate the broadband NLO characteristics of Ti 3 CN NSs.…”

Negative Photoconductivity: Bizarre Physics in Semiconductors

“…In many materials, the coexistence of PPC and NPC was observed under various conditions. The coexistence of PPC and NPC depends on serval factors such as light wavelength, light intensity, applied bias voltage, relative humidity, temperature, composition, etc. ,,,,,− The surface-related phenomenon is widely explored in CNTs and nanowires to investigate their conductivity profile. The adsorption or desorption of moisture molecules on the semiconductor surface can play a vital role in altering the conductivity magnitude. ,, It was observed that the photodesorption of oxygen molecules in double-walled carbon nanotubes (DWNTs) can be the reason for the NPC occurrence.…”

“…The competition between hole concentration (p) and hole mobility (μ p ) leads to the generation of this interesting phenomenon. Another effect can be the illumination intensity and wavelength on photoconductivity. , By varying the illumination intensity, the PPC can switch to NPC. The switching between NPC to PPC was presented in the InAs nanowires (Y. Han et al) .…”

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).…”