Selectively Modulated Photoresponse in Type‐I Heterojunction for Ultrasensitive Self‐Powered Photodetectors

Abstract

Photodetectors based on two‐dimensional (2D) van der Waals heterostructures (vdWHs) have demonstrated great potential in modern nanotechnologies across a wide range of applications. However, due to the severe interface recombination of the photogenerated electron–hole pairs and various absorption edges of constituent layers, they would suffer from low carrier collection efficiency, and the spectral response range of each constituent layer is indistinguishable. Herein, tellurium (Te) nanoflakes with broadband photoresponse are synthesized to construct type‐I InSe/Te vdWHs photodetector, which exhibits an ultralow reverse dark current of 3 × 10−14 A and an ultrahigh current rectification ratio of 108. Moreover, considerable photovoltaic effect of the heterostructure device is observed under illumination, attaining a light on/off ratio of up to 105, a high specific detectivity of 1.77 × 1011 Jones, and a fast response time of 320 µs. Based on type‐I band alignment, the Te layer can collect the photogenerated holes from the InSe layer to suppress the recombination of photogenerated carriers. More importantly, the spectral response of the InSe/Te heterostructure photodetector can be selectively modulated by the InSe layer. This work demonstrates that band alignment engineering of 2D vdWHs holds great potential for developing high‐performance self‐powered photodetectors.

High‐Performance and Polarization‐Sensitive Imaging Photodetector Based on WS2/Te Tunneling Heterostructure

“…However, due to the presence of interface recombination mediated by tunneling via the Shockley-Read-Hall or Langevin models, photocarriers suffer severe losses and poor collection efficiency. [17,22,26] Furthermore, the photoexcited electrons and holes that need to penetrate the heterointerface are both minority carriers in each component, and they tend to be trapped and recombined, [15] resulting in limited responsivity. To improve the performance, several strategies have been exploited.…”

Self‐Powered Te/Wse2 Van Der Waals Heterojunction Photodetectors With High Light On/Off Ratio And Fast Response

“…The photoluminescence (PL) spectra of Te/WSe 2 heterojunction in Figure S1 (Supporting Information) showed a decreased PL intensity compared with that of a single WSe 2 , also indicating the strong interfacial coupling and efficient photogenerated carriers transfer between Te and WSe 2 . [24,32] The Raman spectra of the pristine Te, WSe 2 , and Te/WSe 2 vd-WHs are shown in Figure 2d. The characteristic peaks at 248 and 257 cm −1 in the WSe 2 film correspond to the E 1 2g and A 1g modes, respectively.…”

“…The use of 2D materials in self-powered photodetectors has shown promise, with several reports demonstrating their potential for use in such devices. [22,24] Furthermore, the unique properties of 2D materials may also enable the development of novel photodetector designs that can detect a wider range of wavelengths or have enhanced sensitivity. [25,26] Therefore, continued research in this area is necessary to realize the full potential of 2D materials in self-powered photodetectors.…”

Recent Development of Self‐Supported Alkaline Hydrogen Evolution Reaction Electrocatalysts for Industrial Electrolyzer

“…Constructing heterostructures can regulate electron transfer and active sites due to the existence of coupling interfaces and the synergistic effect of the heterostructures. [ 135 ] For instance, plenty of heterostructures including MoO 2 –FeP, [ 136 ] MoO 3 nanodots/MoS 2 , [ 137 ] NiS 2 /N‐NiMoO 4 , [ 138 ] NiFeO x /CFP, [ 139 ] Co x P@Co 3 O 4 , [ 140 ] and GDY/MoO 3 , [ 141 ] have been extensively constructed for the enhanced HER electrocatalytic performance.…”