Recent Advances in Two‐Dimensional Heterostructures: From Band Alignment Engineering to Advanced Optoelectronic Applications

Abstract

Dynamically engineering the band alignment between materials, especially 2D semiconductors, is critically important for the design of novel devices with superior functions. Here, a review of band alignment engineering in 2D heterostructures and the derived device applications, mainly outlining their potential as photodetectors, photovoltaics, and light‐emitting devices, is provided. Various approaches are summarized, through exploiting the advantages of each component and different device structure, to further improve the performances of the optoelectronic devices. The authors also provide their perspectives on future developments of photoelectric chips based on the newly designed optoelectronic devices.

Van der Waals Epitaxy of Bi2Te2Se/Bi2O2Se Vertical Heterojunction for High Performance Photodetector

“…The band alignment is crucial in heterojunction as it dictates the movement of charge carriers near the interface. [ 35–37 ] Using density function theory, we calculated electronic band structure ( Figure a) and Fermi level energy of 6‐layer Bi 2 Te 2 Se and derived its band edge positions based on the results. A type II band alignment can be concluded as shown in Figure 3b.…”

Indium Selenide/Antimonene Heterostructure for Multifunctional Optoelectronics

“…Up to now, 2-D heterostructures with different layer-bylayer stacked individual 2-D materials through weak physical van der Waals (vdW) interactions have been regarded as an effective strategy to adjust the physical and chemical properties of 2-D materials [9]. On one hand, the electronic properties of 2-D materials can be regulated by constructing vdW heterostructures so that it can be excited under the light of required wavelengths.…”

Band alignment of type-I SnS2/Bi2Se3 and type-II SnS2/Bi2Te3 van der Waals heterostructures for highly enhanced photoelectric responses

“…A combined structure of Bi 2 X 3 (X = Se, Te) and vertical SnS 2 nanosheets can enhance the photon-capturing ability and accelerate charge transportation at the heterostructure interface. Type-I heterostructures, in which the holeand-electron transfer favors the semiconductor with the narrower band gap, are widely used in transistors [31]. Type-II heterostructures, which improve the PEC efficiency by reducing the electron-hole pair recombination, are widely used in photocatalytic water splitting [32].…”