A High‐Speed Photodetector Fabricated with Tungsten‐Doped MoS₂ by Ion Implantation

Abstract

Molybdenum disulfide (MoS2) is a promising 2D semiconductor material for its unique characteristics such as tunable bandgap, high electrical conductivity, and strong light–matter interaction. Presently, many efforts have been made to modulate its properties, such as surface engineering, strain introduction, doping, and so on. Recently, it has been proved that substitutional metal doping is an effective approach to tune the energy bandgap of the aimed material and improve the performance of the device. Conventional metal doping methods will inevitably introduce impurities or defects and cannot control doping regions. Ion implantation is widely used in traditional semiconductor modification processes due to its high efficiency, controllability, and homogeneity. But it is rarely applied to 2D materials because of the damage caused during the implantation process. Here, the SiO2 substrate is implanted by tungsten ion implantation and then the tungsten doping of MoS2 is successfully achieved by chemical vapor deposition (CVD) growth process, while avoiding direct implantation damage to it. The W‐doped MoS2 photodetectors show a high‐speed response with a rise/fall time of 210 ms/160 ms. This work provides a novel doping strategy for metal doping of 2D materials and opens a new avenue to modify 2D materials properties.

Recent progress in plasma modification of 2D metal chalcogenides for electronic devices and optoelectronic devices

“…Tungsten plasma has been injected into a silicon oxide substrate followed by CVD growth of molybdenum sulfide to gain effective metal substitution doping and avoid the damage caused by direct doping. 69…”

“…2(d)). In addition, plasma-based substitution doping has made great contributions in photovoltaic and photoconductivity, 69,72,73 photoluminescence enhancement and quenching, 74 and surface Raman enhancement. 75,76 Yu et al 62 treated SnS 2 by O 2 plasma to fill some inherent sulfur vacancies, producing an additional defect state above the Fermi level.…”

“…Tungsten plasma has been injected into a silicon oxide substrate followed by CVD growth of molybdenum sulfide to gain effective metal substitution doping and avoid the damage caused by direct doping. 69 Based on the realization of controllable p-doping, the doped 2D MCs can construct homojunctions with the undoped area, and attain more complex functions. Covalent p-type doping of MoS 2 was accomplished through mild nitrogen plasma modulation, and p-n homojunctions were prepared.…”

Synthesis of continuous MoS2:Er films and their enhanced NIR photoresponse for photo communication

“…, introducing a dopant into the host, results from the added impurity energy levels 13 and trap states 14 or the altered electron transport characteristics. 15 Compared with conventional dopants, certain rare earth ions, especially Er 3+ ions, exhibit excellent light absorption in the NIR region benefiting from their unique outer electronic structure, which makes them more potential dopants for enhancing the NIR response of MoS 2 . 16,17…”

“…Element doping, i.e., introducing a dopant into the host, results from the added impurity energy levels 13 and trap states 14 or the altered electron transport characteristics. 15 Compared with conventional dopants, certain rare earth ions, especially Er 3+ ions, exhibit excellent light absorption in the NIR region benefiting from their unique outer electronic structure, which makes them more potential dopants for enhancing the NIR response of MoS 2 . 16,17 Numerous techniques have been reported for preparing doped semiconductor films, such as magnetron sputtering, 18 atomic layer deposition, 19 pulsed laser deposition, 20 chemical vapor deposition 21 and spin coating.…”