Flexible SnSe Photodetectors with Ultrabroad Spectral Response up to 10.6 μm Enabled by Photobolometric Effect

Abstract

A broad spectral response is highly desirable for radiation detection in modern optoelectronics; however, it still remains a great challenge. Herein, we report a novel ultrabroadband photodetector based on a high-quality tin monoselenide (SnSe) thin film, which is even capable of detecting photons with energies far below its optical band gap. The wafer-size SnSe ultrathin films are epitaxially grown on sodium chloride via the 45° in-plane rotation by employing a sputtering method. The photodetector delivers sensitive detection to ultraviolet–visible–near infrared (UV–Vis–NIR) lights in the photoconductive mode and shows an anomalous response to long-wavelength infrared at room temperature. Under the mid-infrared light of 10.6 μm, the fabricated photodetector exhibits a large photoresponsivity of 0.16 A W–1 with a fast response rate, which is ∼3 orders of magnitude higher than other results. The thermally induced carriers from the photobolometric effect are responsible for the sub-bandgap response. This mechanism is confirmed by a temperature coefficient of resistance of −2.3 to 4.4% K–1 in the film, which is comparable to that of the commercial bolometric detectors. Additionally, the flexible device transferred onto polymer templates further displays high mechanical durability and stability over 200 bending cycles, indicating great potential toward developing wearable optoelectronic devices.

Recent Advances in 2D Materials for Photodetectors

“…Xu and his colleagues prepared a photodetector based on a high‐quality SnSe membrane by utilizing epitaxial growth method, which displays broadband photoresponse from UV to IR region, high responsivity of 0.16 A W −1 and D * of 3.9 × 10 7 Jones under 404 nm laser illumination, which is competitive with commercial detectors. [ 50 ] Similarly, the photodetector also shows mechanical flexibility and stability. After 200 bending cycles, the current–voltage and current–time curves have not significantly changed.…”

Manipulating the Light‐Matter Interaction of PtS/MoS2 p–n Junctions for High Performance Broadband Photodetection

“…For the photodetector, responsivity ( R ) and specific detectivity ( D *) are the key parameters to estimate the detection performance. The value of R indicates the photocurrent generated by excitation per unit power on the effective area and D * is defined as the capacity of the detector to detect weak light signals which could be respectively extracted from the following formulas: [ 41,42 ] where the I p is the photocurrent, I d is the dark current, P opt is the light power, A is the effective device area, and e is the electronic charge. Figure 4d shows the profiles of the responsivity as a function of gate voltage under wavelength of 400 nm with different power density.…”

“…It is well known that the value of θ is closely related to the photocurrent generation mechanism which can be separated into two types for most photodetector based on 2D material. [ 42 ] One is the photoinduced carrier excitation including photoconductive effect, photovoltaic effect, and photogating effect. [ 44 ] Another one is originated from thermal effect.…”

Ternary Ta2PdS6 Atomic Layers for an Ultrahigh Broadband Photoresponsive Phototransistor

“…The performance of the main 2D material‐based photodetectors with their highest records is summarized in Figure 6e, including Ta 2 PdS 6 , PtSe 2 , [ 11 ] PdSe 2 , [ 6 ] ReS 2 , [ 33 ] PtS 2 , [ 31 ] MoS 2 , [ 35 ] WSe 2 , [ 38 ] InSe, [ 37 ] In 2 Se 3 , [ 36 ] GaTe, [ 32 ] black phosphorous (BP), [ 34 ] GaSe, [ 39 ] SnSe 2 , [ 47 ] tellurene, [ 48 ] Bi 2 O 2 Se, [ 49 ] TiS 3 , [ 27 ] and SnSe. [ 50 ] A comparison of the photoresponsivity, detectivity, photoconductive gain, air stability, maximum detection wavelength, and carrier mobility found for the abovementioned 2D devices and our fabricated Ta 2 PdS 6 nanowire‐based device shows that our device exhibits the excellent comprehensive performance. The excellent comprehensive optoelectronic performance makes 2D Ta 2 PdS 6 a promising commercial optoelectronic channel material for various applications in image sensing, communications, environmental monitoring, remote control, etc.…”

“…V bg = −50 V, V ds = 1 V. e) Comparison of high‐performance phototransistors based on 2D materials, including PtSe 2 , [ 11 ] PdSe 2 , [ 6 ] ReS 2 , [ 29 ] PtS 2 , [ 27 ] MoS 2 , [ 31 ] WSe 2 , [ 34 ] InSe, [ 33 ] In 2 Se 3 , [ 32 ] GaTe, [ 28 ] black phosphorus (BP), [ 30 ] GaSe, [ 35 ] SnSe 2 , [ 36 ] Tellurene, [ 48 ] Bi 2 O 2 Se, [ 49 ] TiS 3 , [ 27 ] and SnSe. [ 50 ]…”