Black Phosphorous/Indium Selenide Photoconductive Detector for Visible and Near‐Infrared Light with High Sensitivity

Abstract

cooling system is usually needed to ensure that these traditional photodetectors possess a relatively high performance. Since the first 2D material, graphene, was discovered in 2004, [1] 2D material-based photodetectors have attracted considerable attention. [2,3] Graphene is a promising material for photodetectors due to its ultrabroadband absorption spectrum, which includes the whole ultraviolet (UV) spectrum and ranges up to terahertz wavelengths. [4][5][6] However, the development of photodetectors based on pristine graphene is limited by the short lifetime of photoexcited carriers and the low absorption efficiency of incident photons. [7] Furthermore, pristine graphene with a zero bandgap will result in a large dark current, which is not suitable for highly responsive photo detectors. Although many methods can be applied to give graphene a semiconducting transport property and small bandgap, the photoresponse capability of graphene with small bandgap, especially for a certain spectral range, is still not comparable to that of other 2D semiconductors. [8,9] In addition to graphene, semiconducting transition metal dichalcogenides (TMDs), such as WS 2 , WSe 2 , MoS 2 , MoTe 2 , etc., [10][11][12][13][14][15] have been shown to possess remarkable optical and electronic properties [16] and are expected to be promising basic materials for broadband, high-sensitivity photodetectors due to their various bandgaps, ranging from less than 1 eV to well above 2.5 eV. [17][18][19] However, due to their relatively large bandgaps, they are not suitable for infrared light detection.Black phosphorous (BP), with a direct bandgap of ≈1.5 eV for the monolayer form and 0.3 eV for bulk form, [20,21] which covers the near-and mid-infrared band and exhibits unique properties due to its high carrier mobility, [22][23][24] compatibility with a diverse range of substrates, and moderate bandgap. These unique properties make BP a promising candidate for broadband optoelectronic applications. [25][26][27][28] However, the reactivity of BP to oxygen under ambient conditions will lead to compositional and physical changes, causing BP to lose its advantageous electronic and optical properties. This reactivity hinders the practical application of BP for broadband photodetectors with rapid response time. [29,30] In addition, BP-based photodetectors have a weak response to visible light due to the bandgap. To extend the photoresponse range of BP, a BP/ MoS 2 heterojunction was fabricated by Hong et al., and the 2D materials offer tremendous opportunities for designing and investigating multifunctional high-performance electronic and optoelectronic devices. In this contribution, a photogate vertical structure is devised by vertically stacking layered indium selenide (InSe) on top of layered black phosphorous (BP). The photodetector built with the vertical structure possesses a wide response range from 405 to 1550 nm, and the photodetector exhibits a relatively fast (≈22 ms) response and high responsivity of ≈53.80 A W −1 at λ = 655 nm and 43.11 ...

Recent Progress of Two-Dimensional Thermoelectric Materials

“…A monolayer phosphorene and a few-layer phosphorene have been successfully exfoliated from bulk BP in 2014 and have attracted a tremendous research interest in the past few years [28,112,113]. As a novel elementary 2D material, the few-layer BP has gained tremendous attention in theoretical and experimental investigations [114][115][116][117][118][119]. Due to its unique crystal structure and in-plane anisotropic properties, BP has been widely studied in various fields including in the development of photodetectors [116,120,121], cancer therapies [115,122,123], supercapacitors [124], field-effect transistors (FETs) [125,126], batteries [127,128], and thermoelectric devices [39,98,[129][130][131][132][133].…”

Two-Dimensional Tellurium: Progress, Challenges, and Prospects

“…The environmental stability is another important property of 2D materials. For many 2D materials, such as BP [19,21,[96][97][98] and TMDCs [99][100][101][102], instability has severely hindered their further development in both academic and industrial applications. In sharp contrast, extraordinary environmental stability has been demonstrated for various thicknesses of 2D Te (ranging from few-layer to monolayer).…”

“…Since atomically thin graphene flakes were discovered in 2004 [5,6], two-dimensional (2D) materials have triggered intensive research interest for the fabrication of nanodevices on an industrial scale [7][8][9][10][11][12][13][14][15]. However, the development of 2D materials faces significant challenges, such as the zero bandgap of graphene [16,17], the environmental instability of black phosphorus (BP) [18][19][20][21][22], the low current mobility of transition metal dichalcogenides (TMDCs) [23], and the lack of large-scale and efficient synthesis methods. In 2017, 2D nanoflakes of Te were successfully fabricated [24], which possess superior properties compared to other existing 2D materials, including excellent environmental stability, better oxidation and hydration catalytic activity, a tunable bandgap, improved thermoelectric, and nonlinear optical responses, and a high carrier mobility (~ 10 3 cm 2 V −1 s −1 ) at room temperature [25].…”

Two-Dimensional Platinum Diselenide: Synthesis, Emerging Applications, and Future Challenges

“…It has been widely applied in many fields such as optical communication, industrial automatic control, and military [147][148][149]. 2D materials, including graphene, BP, and TMDCs, are considered to be promising candidates for high-performance photodetectors due to their excellent properties and complementary metal oxide semiconductor compatible [147,[150][151][152][153][154][155]. However, it is still challenge to fabricate high responsivity 2D material-based photodetectors along with ultrafast response.…”