An ultrasensitive molybdenum-based double-heterojunction phototransistor

Abstract

Two-dimensional (2D) materials are promising for next-generation photo detection because of their exceptional properties such as a strong interaction with light, electronic and optical properties that depend on the number of layers, and the ability to form hybrid structures. However, the intrinsic detection ability of 2D material-based photodetectors is low due to their atomic thickness. Photogating is widely used to improve the responsivity of devices, which usually generates large noise current, resulting in limited detectivity. Here, we report a molybdenum-based phototransistor with MoS2 channel and α-MoO3-x contact electrodes. The device works in a photo-induced barrier-lowering (PIBL) mechanism and its double heterojunctions between the channel and the electrodes can provide positive feedback to each other. As a result, a detectivity of 9.8 × 1016 cm Hz1/2 W−1 has been achieved. The proposed double heterojunction PIBL mechanism adds to the techniques available for the fabrication of 2D material-based phototransistors with an ultrahigh photosensitivity.

Efficient Suppression of Charge Recombination in Self-Powered Photodetectors with Band-Aligned Transferred van der Waals Metal Electrodes

“…The calculated values are 236 and 312 μs for τ r and τ f , respectively. The fast response speed of our device is comparable to the highest previously reported value obtained from various 2D material-based photodetectors …”

“…The two-step separation of electrons and holes contributes to the high value of α and high performance of the device. At the same time, compared to the general photogating-enabled photodetectors, which rely on traps, our device ought to be intrinsically faster due to the absence of photogenerated carrier trapping . Contrary behavior can be expected for the deposited Au–ReSe 2 –Ag device, the Fermi level is pinned around the defect levels, leading to a much weaker built-in potential (Figure c).…”

Pulsed‐Laser‐Deposition Fabricated ZnIn2S4 Photodetectors with Excellent ON/OFF Switching Characteristics toward High‐Temperature‐Resistant Photodetection Applications

“…[2][3][4][5] However, photodetectors based on traditional 2DLMs also suffer from some tough challenges. To begin with, the 2D devices are commonly constructed by uncontrollable methods and typically only a single prototype device is available in most of the previous studies, [6][7][8][9][10][11] while the preparation of multiple optoelectronic devices within one chip has been challenging to realize yet, especially for the common micro-mechanical exfoliation and chemical vapor deposition (CVD) methods. However, onchip integration is an indispensable precondition for practical engineering applications.…”

Oxygen deficient α-MoO3 with enhanced adsorption and state-quenching of H2O for gas sensing: a DFT study

“…14–16 Furthermore, the work function of α-MoO 3 is tunable with the defective levels induced by V O , which has been utilized in the design of the MoS 2 /α-MoO 3- x heterojunction as a phototransistor with a high detectivity of 9.8 × 10 16 cm Hz 1/2 W −1 . 17 Meanwhile, the defective levels can achieve near infrared (NIR) absorption and localized surface plasmon resonance (LSPR) effects, making α-MoO 3- x promising as a biodegradable nanoagent for photothermal cancer therapy. 18,19…”