2D Homojunctions for Electronics and Optoelectronics

Abstract

In the post‐Moore era, 2D materials with rich physical properties have attracted widespread attention from the scientific and industrial communities. Among 2D materials, the 2D homojunctions are of great promise in designing novel electronic and optoelectronic devices due to their unique geometries and properties such as homogeneous components, perfect lattice matching, and efficient charge transfer at the interface. In this article, a pioneering review focusing on the structural design and device application of 2D homojunctions such as p–n homojunctions, heterophase homojunctions, and layer‐engineered homojunctions is provided. The preparation strategies to construct 2D homojunctions including vapor‐phase deposition, lithium intercalation, laser irradiation, chemical doping, electrostatic doping, and photodoping are summarized in detail. Specifically, a careful review on the applications of the 2D homojunctions in electronics (e.g., field‐effect transistors, rectifiers, and inverters) and optoelectronics (e.g., light‐emitting diodes, photovoltaics, and photodetectors) is provided. Eventually, the current challenges and future perspectives are commented for promoting the rapid development of 2D homojunctions.

2D Bi2Se3 materials for optoelectronics

“…In this case, the MOF nanoparticles can not only serve as a photosensitive material to absorb incident light, but also act as a photogate layer to regulate the channel conductance of Bi 2 Se 3 channel ( Figure 5 E), thereby enhancing the photoconductivity gain of the device and realizing high-performance photodetection. As displayed in Figure 5 F, the resultant photodetector demonstrated outstanding responsivity up to 4725 A W −1 with high detectivity of 3.5 × 10 13 Jones under 1500 nm illumination with power density of 0.012 mW cm −2 at V ds = 1 V and V gs = 60 V ( Wang et al., 2021a , 2021b , 2021c , 2021d ).

Figure 5 Visible-infrared photodetection of 2D Bi 2 Se 3 -based heterostructures (A) Schematic diagrams of Bi 2 Se 3 /WSe 2 tunneling heterostructure with electron-hole pair generation and tunneling under illumination.

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“…The dark current of the heterostructure was obviously suppressed, but the responsivity still has room for improvement because of the weak optical absorption that originates from its atomically thin nature. In view of this, Zhai and co-authors constructed a hybrid heterostructure by integrating metal-organic frameworks (MOFs) nanoparticles with strong optical absorption on the surface of 2D Bi 2 Se 3 flakes ( Figure 5 D) ( Wang et al., 2021a , 2021b , 2021c , 2021d ). In this case, the MOF nanoparticles can not only serve as a photosensitive material to absorb incident light, but also act as a photogate layer to regulate the channel conductance of Bi 2 Se 3 channel ( Figure 5 E), thereby enhancing the photoconductivity gain of the device and realizing high-performance photodetection.…”

“…Compared with their bulk counterparts, 2D layered materials usually show unique features because of quantum confinement effect along the vertical direction of the 2D plane ( Akinwande et al., 2014 ; Liu et al., 2020a , 2020b , 2020c ; Ricciardulli et al., 2021 ). Atomically smooth surfaces without dangling bonds enable them to be compatible with any 2D materials and mature complementary metal oxide semiconductor (CMOS) process without considering lattice matching ( Akinwande et al., 2019 ; Iannaccone et al., 2018 ; Liang et al., 2019 ; Liu et al., 2019a , 2019b ; Wang et al., 2021a , 2021b , 2021c , 2021d ). Moreover, the electronic band structures of 2D layered materials cover a wide range of electromagnetic spectrum, meaning that diverse optical and electrical properties reside in their family ( Liu et al., 2021a , 2021b ; Xia et al., 2014 ).…”

“…In the last decade, a wealth of 2D layered materials have been isolated from bulk crystals or been fabricated through bottom-up synthesis ( Cai et al., 2018 ; Fang et al., 2021 ; Han et al., 2019a , 2019b ; Li et al., 2017 ; Varoon et al., 2011 ; Wang et al., 2020a , 2020b ; Zhou et al., 2018 ). Their fundamental physical properties and demonstrative functional devices have been thoroughly studied ( Koppens et al., 2014 ; Sierra et al., 2021 ; Wang et al., 2019a , 2019b , 2019c , 2021a , 2021b , 2021c , 2021d )). These thereby vastly promote the application of 2D layered materials in next-generation advanced devices.…”

High-sensitivity shortwave infrared photodetectors of metal-organic frameworks integrated on 2D layered materials

“…Shortwave infrared (SWIR) photodetector is one of the core components in modern electronics industry, which demonstrates a vital role in various fields such as military defense, industrial production, medical diagnosis and optical communication [1][2][3][4][5]. Two-dimensional layered materials (2DLMs) with narrow bandgap and high mobility are considered as the promising candidates for next-generation infrared optoelectronics due to their unique structures and photoelectric properties [6][7][8][9][10][11]. At present, considerable efforts have been devoted to demonstrating the SWIR photodetection performance of 2DLMs [1,5].…”