Wafer-Scale Synthesis of High-Quality Semiconducting Two-Dimensional Layered InSe with Broadband Photoresponse

Abstract

Large-scale synthesis of two-dimensional (2D) materials is one of the significant issues for fabricating layered materials into practical devices. As one of the typical III-VI semiconductors, InSe has attracted much attention due to its outstanding electrical transport property, attractive quantum physics characteristics, and dramatic photoresponse when it is reduced to atomic scale. However, scalable synthesis of single phase 2D InSe has not yet been achieved so far, greatly hindering further fundamental studies and device applications. Here, we demonstrate the direct growth of wafer-scale layered InSe nanosheets by pulsed laser deposition (PLD). The obtained InSe layers exhibit good uniformity, high crystallinity with macro texture feature, and stoichiometric growth by in situ precise control. The characterization of optical properties indicates that PLD grown InSe nanosheets have a wide range tunable band gap (1.26-2.20 eV) among the large-scale 2D crystals. The device demonstration of field-effect transistor shows the n-type channel feature with high mobility of 10 cm V s. Upon illumination, InSe-based phototransistors show a broad photoresponse to the wavelengths from ultraviolet to near-infrared. The maximum photoresponsivity attains 27 A/W, plus a response time of 0.5 s for the rise and 1.7 s for the decay, demonstrating the strong and fast photodetection ability. Our findings suggest that the PLD grown InSe would be a promising choice for future device applications in the 2D limit.

2D Metal Chalcogenides for IR Photodetection

“…In the family of 2D group IIIA metal chalcogenides, 2D In‐based chalcogenides including In 2 S 3 , In 2 Se 3 , In 2 Te 3 , and InSe, have shown great promise in IR photodetection applications. As shown in Figure a,b, our group has successfully synthesized ultrathin 2D β‐In 2 S 3 by improved space‐confined CVD method and has explored the broad detection up to 900 nm .…”

“…The 2D α‐In 2 Te 3 film possesses stable photoswitching behavior at 1064 nm with a superior responsivity of ≈5 A W −1 , a fast response time of 15 ms, and a specific detectivity of 10 11 Jones . Another 2D In‐based semiconductors, InSe has a narrower direct bandgap ( E g ≈ 1.3 eV) that offers a broad photoresponse up to NIR region . Recently, Feng et al have discovered that the multiple reflection interference could enhance the light absorption and lead to a thickness‐dependent photoresponse .…”

Atomic-scale mechanisms of defect- and light-induced oxidation and degradation of InSe

“…20,21 The thickness-dependent direct band gap of thick InSe sheets allows a broad excitonic emission. 22 These unique properties trigger many studies on the growth, [23][24][25] exfoliation, 26 and applications of InSe, for example, in optoelectronics, [27][28][29][30] sensors, and photovoltaics. 19,28,31 However, the performance of InSe-based transistors at ambient conditions 16 or under external fields 32 was found to be unsatisfying due to the degradation of their performance.…”

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

“…In addition, due to difficulties in exfoliation and lack of thickness‐controlled synthesis methods, previous reports were unable to study layered‐dependent properties of the 2D layered material, and to our knowledge, characterization or properties of GaS less than 3 layers (3L) are missing. Furthermore, although other members in the group‐III monochalcogenide‐layered materials with similar structures (GaSe, GaTe, InSe) have attracted intense attention as they have demonstrated superior optical properties, including ultra‐high second‐harmonic generation, giant piezo‐phototronic response, polarization‐dependent absorption, etc., properties of GaS with wide potential remain unexplored as a result of unanswered stability issues and unsatisfying samples. Recently, our group has developed a simple and atmospheric pressure chemical vapor deposition (CVD) method for the growth of 2D GaS crystals, which paved way for further study of the material's stability and layer‐dependent properties.…”