Robust Piezo-Phototronic Effect in Multilayer γ-InSe for High-Performance Self-Powered Flexible Photodetectors

Abstract

The piezo-phototronic effect has been promising as an effective means to improve the performance of two-dimensional (2D) semiconductor based optoelectronic devices. However, the current reported monolayer 2D semiconductors are not regarded as suitable for actual flexible piezotronic photodetectors due to their insufficient optical absorption and mechanical durability, although they possess strong piezoelectricity. In this work, we demonstrate that, unlike 2H-phase transition-metal dichalcogenides, γ-phase InSe with a hexagonal unit cell possesses broken inversion symmetry in all the layer numbers and has a strong second-harmonic generation effect. Moreover, driven by the piezo-phototronic effect, a flexible self-powered photodetector based on multilayer γ-InSe, which can work without any energy supply, is proposed. The device exhibited ultrahigh photon responsivity of 824 mA/W under light illuminations of 400 nm (0.368 mW/cm 2 ). Moreover, the responsivity and response speed of this photodetector were enhanced further by as much as 696% and 1010%, respectively, when a 0.62% uniaxial tensile strain was applied. Our devices exhibit high reliability and stability during a 6 month test time. These significant findings offer a promising pathway to construct high-performance flexible piezo-phototronic photodetectors based on multilayer 2D semiconductors.

Recent Advances in Strain-Induced Piezoelectric and Piezoresistive Effect-Engineered 2D Semiconductors for Adaptive Electronics and Optoelectronics

“…Recently, the analogous experiment was also performed on 2D multilayer γ-phase InSe photodetector. The responsivity and response speed of this photodetector were enhanced further by as much as 696% and 1010% when the device was subjected to a 0.62% uniaxial tensile strain due to the piezo-phototronic effect [204]. Zhang et al [205] designed and fabricated a flexible photodiode based on single-layer MoS 2 lateral p-n homojunction by chemical doping (Fig.…”

“…Figure 17e, f shows the device under 0.65% tensile strain, the photoresponsivity increase from 0.22 to 0.37 A W −1 and the photo-response time decrease from 244 to 214 μs. Dai et al [204] demonstrated the photocurrent of β-InSe multilayers-based photodetector achieved a 211% enhancement ratio under a uniaxial tensile strain of 0.62% due to piezoresistive effect. The piezoresistive effect in 2D semiconductors can reduce the barrier heights of two Schottky junctions simultaneously (Fig.…”

Tunable Optical Properties of 2D Materials and Their Applications

“…With 0.31% tensile strain (see Figure 6d), the photodetector exhibited an ultrahigh photoresponsivity of 824 mA W −1 under the 400 nm illuminations at zero bias, a high detectivity of 1.7 × 10 12 Jones, and a high response speed of 20 µs. [ 118 ] Moreover, Pal et al. proposed a plasmonic Au nanoparticle loaded g‐C 3 N 4 over CdS/ZnO heterojunction, leveraging the piezophototronic effect.…”

Nested Inverse Opal Perovskite toward Superior Flexible and Self‐Powered Photodetection Performance

“…We also compare the performance parameters of NIO device with some previously reported flexible perovskite and inorganic materials‐based photodetectors (Figure 3f). [ 21,41–48 ] The detailed parameters are supplemented in Table S2 (Supporting Information). Obviously, the figure of merits of NIO device are comparable to and even higher than most of those devices.…”