Conformal MoS₂/Silicon Nanowire Array Heterojunction with Enhanced Light Trapping and Effective Interface Passivation for Ultraweak Infrared Light Detection

Abstract

2D layered materials have attracted considerable attention for fabricating IR photodetectors. However, performance, especially for weak signal detection, of these IR photodetectors is often limited by the low absorbance of the very thin active materials as well as unsuppressed dark currents. Herein, a photodetector with high sensitivity for ultraweak IR signals based on a conformal MoS2/silicon nanowire array heterojunction with an ultrathin Al2O3 interfacial passivation layer is reported. The conformal light‐trapping nanoarray structure can greatly enhance broadband IR absorption, while the Al2O3 layer can suppress interface carrier recombination effectively and thus lower reverse dark current. The photodetectors exhibit broadband photoresponse ranging from 300 to 1600 nm, low noise current of 0.11 pA Hz−1/2, large responsivity up to 0.61 A W−1 at zero bias voltage, and high specific detectivity of 1011–1012 Jones. Significantly, the devices are capable of detecting ultraweak IR signals (e.g., 100 pW at 808 nm and 3 nW at 1310/1550 nm) with high on–off ratios without applying any external bias. This work proposes a new strategy to enhance light absorption of 2D materials and construct high‐quality junction based on them, which is promising for low‐cost and high‐performance optoelectronic devices.

In situ integration of Te/Si 2D/3D heterojunction photodetectors toward UV-vis-IR ultra-broadband photoelectric technologies

“…S11 †), which represents one of the record-high values among state-of-the-art optoelectronic devices. [40][41][42][43][44][45] Benefiting from the relatively small bandgap of Te (∼0.335 eV), 26 which gives rise to wide-range light absorption covering the ultraviolet to the infrared (Fig. S12 †), the effective spectral range of the Te/Si heterojunction photodetector has been markedly extended into the longer-wavelength region as compared to that for pure Si photodetectors.…”

Boosting the Sensitivity of WSe2 Phototransistor via Janus Interfaces with 2D Perovskite and Ferroelectric Layers

“…As shown in Figure g, the device still displays an obvious photoresponse even under ultraweak light intensity as low as 1.6 nW/cm 2 , while R is 2.3 × 10 5 A/W and D * is 4.1 × 10 14 Jones under the test condition of V g = 0, V ds = 0.1 V (the spectral noise density measured under dark conditions with V ds = 0.1 V is shown in Figure S10). Figure h summarizes the competitive values of threshold light intensity in the field of 2D semiconductor-based photodetectors, ,,,,,,,, in which our device is the best. The excellent performance in weak-light detection ability for our device mainly stems from the vertical Janus-interface device architecture, combining with the upper perovskite for providing generous photoexcited holes to WSe 2 and the lower ferroelectric film for suppressing the dark current dramatically.…”

“…2D semiconductors are good candidates for next-generation optoelectronic devices, partly due to the efficient gate control on their carrier dynamics, − which can be further strengthened and richened by the utilization of ferroelectric dielectrics. , In BA/WSe 2 /HZO, the application of gate voltage has two different effects: the ferroelectric polarization-assisted interfacial trapping effect and the electrostatic electric field induced carrier doping effect. The former effect is evidenced by the clockwise (anticlockwise) hysteresis on the n-type (p-type) side of the transfer curves in Figure d.…”

Research progress of silicon nanowires array photodetectors

“…[81] 21 / 33 2022 年，Wang 等人 [15] 通过真空热蒸发法获得了高质量的拓扑绝缘体 Bi 图 12 n-Bi 2 Se 3 /p-SiNWs 光电探测器在探测波长范围内的响应率和探测率 [14] Figure 12 Responsivity and detectivity of n-Bi 2 Se 3 /p-SiNWs photodetector in the detection wavelength range. [14] 图 13 高质量"共形"Si-NW/MoS 2 异质结光电探测器的制备流程 [83] Figure 13 Preparation process for high-quality "Conformal" Si-NW/MoS 2 heterojunction photodetector. [83] 2022 年，Mao 等人 [83] 合理设计并构建了用于超微弱红外光探测的、具有 Al 图 14 柔性硅基光电探测器的制备原理示意图 [89] Figure 14 Schematic diagram of the preparation principle for flexible silicon based photodetectors.…”