High-Performance Transparent Ultraviolet Photodetectors Based on InGaZnO Superlattice Nanowire Arrays

Abstract

Due to the efficient photocarrier separation and collection coming from their distinctive band structures, superlattice nanowires (NWs) have great potential as active materials for high-performance optoelectronic devices. In this work, InGaZnO NWs with superlattice structure and controllable stoichiometry are obtained by ambient-pressure chemical vapor deposition. Along the NW axial direction, perfect alternately stacking of InGaO(ZnO) 4 + blocks and InO 2 − layers is observed to form a periodic layered structure. Strikingly, when configured into individual NW photodetectors, the Ga concentration is found to significantly influence the amount of oxygen vacancies and oxygen molecules adsorbed on the NW surface, which dictate the photoconducting properties of the NW channels. Based on the optimized Ga concentration (i.e., In 1.8 Ga 1.8 Zn 2.4 O 7 ), the individual NW device exhibits an excellent responsivity of 1.95 × 10 5 A/W and external quantum efficiency of as high as 9.28 × 10 7 % together with a rise time of 0.93 s and a decay time of 0.2 s for the ultraviolet (UV) photodetection. Besides, the obtained NWs can be fabricated into large-scale parallel arrays on glass substrates as well to achieve fully transparent UV photodetectors, where the performance is on the same level or even better than many transparent photodetectors with high performance. All the results discussed above demonstrate the great potential of InGaZnO superlattice NWs for next-generation advanced optoelectronic devices.

Controlling Defects in Continuous 2D GaS Films for High‐Performance Wavelength‐Tunable UV‐Discriminating Photodetectors

“…As shown in Figure h,i, the I – t (current–time) curve, with the UV light of 1.25 mW cm –2 switching on and off every 10 s, the stoichiometric GaS shows very stable and consistent performance with a sharp edge, indicating instant response. The response time is less than 66 ms (Figure S6, Supporting Information), which is two to three orders less than other visible‐light blind UV photodetectors (Table S1, Supporting Information) . However, the photocurrent of GaS 0.87 decreased drastically as soon as the light was on, and continued with every switching on of the light, dropping to only half of its starting values after only a total of 110 s exposure.…”

Influence of Cation Substitution on the Complex Structure and Luminescent Properties of the ZnkIn2Ok+3 System

“…2,5 Other noteworthy features of this system and, in particular, in the case of In 2-x Ga x O 3 (ZnO) m nanowires, are the improvement of the thermoelectric figure of merit by 2.5 orders of magnitude, in comparison to undoped ZnO nanowires, and the excellent sensitivity to ultraviolet light irradiation as photodetectors. [21][22][23] In the case of Al 3+ doping, Košir et al 24 reported the improvement of the thermoelectric properties caused by the small addition of Al 3+ in Zn 5 In 2 O 8 ceramics. On the other hand, only few studies about the influence of In 3+ substitution in the luminescent properties of IMZOs (M=Ga, Al) performed on microwires have been reported so far.…”

Quantum Artificial Synapses

“…[50] In these cases, the interaction of simultaneous light pulses with adsorbed and bulk oxygen in the surface depletion region play a key role in regulating the NW conductance, that is, the synaptic weight. [9,51] In a recent work, both volatile and non-volatile resistive switching have been achieved in Ag-contacted ZnO nanowire devices, mainly enabled by the atomic Ag diffusion along the NW (Figure 2f,g), which well emulate the ion migration dynamics in biological synapses. [35] With detailed investigation of the memristive mechanism in the Ag-ZnO system, the underlying electrochemical fundamentals of filament formation/dissolution highlight the Ag + /Ag redox reactions and transport characteristics on the crystalline NW surface.…”