Self-Powered SnS_1–xSe_x Alloy/Silicon Heterojunction Photodetectors with High Sensitivity in a Wide Spectral Range

Abstract

Alloy engineering and heterostructures designing are two efficient methods to improve the photosensitivity of two-dimensional (2D) material-based photodetectors. Herein, we report the first-principle calculation about the band structure of SnS1–x Se x (0 ≤ x ≤ 1) and synthesize these alloy nanosheets. Systematic measurements indicate that SnS0.25Se0.75 exhibits the highest hole mobility (0.77 cm2·V–1·s–1) and a moderate photoresponsivity (4.44 × 102 A·W–1) with fast response speed (32.1/57.5 ms) under 635 nm irradiation. Furthermore, to reduce the dark current and strengthen the light absorption, a self-driven SnS0.25Se0.75/n-Si device has been fabricated. The device achieved a preeminent photo-responsivity of 377 mA·W–1, a detectivity of ∼1011 Jones and I light/I dark ratio of ∼4.5 × 102. In addition, the corresponding rising/decay times are as short as 4.7/3.9 ms. Moreover, a broadband sensitivity from 635 to 1200 nm is obtained and the related photoswitching curves are stable and reproducibility. Noticeably, the above parameters are comparable or superior to the most of reported group IVA layered materials-based self-driven photodetectors. Last, the synergistic effects between the SnS0.25Se0.75 nanosheets and the n-Si have been discussed by the band alignment. These brilliant results will pave a new pathway for the development of next generation 2D alloy-based photoelectronic devices.

Interface Engineering Ti3C2 MXene/Silicon Self‐Powered Photodetectors with High Responsivity and Detectivity for Weak Light Applications

“…From the magnified plot for a single response cycle (Figure 5b), the rise time τ r and decay time τ d of our device are found to be 0.14 and 1.6 ms, respectively. The response speed is faster than Ti 3 C 2 /Si, [21] Ti 3 C 2 /perovskite, [22] SnSSe/ Si [43] heterojunction PDs in literatures, and is comparable to the graphene/Si PD, [28] but slower than WS 2 /Si, [41] MoS 2 /Si, [40] MoSe 2 /Si, [44] MoTe 2 /Si [7] PDs. However, the solution-processable fabrication of MXene electrode is competitive for largescale and low-cost PDs.…”

“…[38][39][40][41][42] Figure 4e compares the Ti 3 C 2 / SiO x, Reg /Si PD with previous reports on Si based heterojunction self-powered PDs. [7,[38][39][40][41][42][43][44][45] The R and D* of commercial Si and Ge photodiodes (from Thorlabs, Inc.) are shown as well for comparison. Notably, the presented Ti 3 C 2 /SiO x, Reg /Si photodetector with high detectivity and responsivity stands out in this comparison.…”

2D WS2 Based Asymmetric Schottky Photodetector with High Performance

“…Meanwhile, the self‐powered parameters of short‐circuit current ( I sc ) and open‐circuit voltage ( V oc ) are observed, indicating a photovoltaic effect in the device due to the built‐in electric field. [ 43 ]…”

Copper Iron Sulfide Nanocrystal‐Bulk Silicon Heterojunctions for Broadband Photodetection

“…Besides these studies, the concept of extending the range of photodetection by making heterojunctions of two semiconductors with different bandgaps has been successfully utilized in the past. [ 40–43 ] A majority of these studies employ type‐I [42] or type ‐II [ 41 ] heterojunctions to separate carriers and further enhance carrier lifetimes and mobilities. This significantly improves the gain and responsivity of such devices.…”

“…[ 42,43 ] As a consequence of the high internal gain and long carrier dwell times, these devices exhibit millisecond response times. [ 40–42 ] In our devices a gain mechanism is absent and allows us to elicit significantly shorter device response times of 20 µs. Despite the short response times, we are able to observe high detectivities in the IR region.…”