Abstract
Two-dimensional molybdenum disulfide (MoS2) is a promising material for ultrasensitive photodetector owing to its favourable band gap and high absorption coefficient. However, their commercial applications are limited by the lack of high quality p-n junction and large wafer scale fabrication process. A high speed Si/MoS2 p-n heterojunction photodetector with simple and CMOS compatible approach has been reported here. The large area MoS2 thin film on silicon platform has been synthesized by sulfurization of RF-sputtered MoO3 films. The fabricated molecular layers of MoS2 on silicon offers high responsivity up to 8.75 A/W (at 580 nm and 3 V bias) with ultra-fast response of 10 μsec (rise time). Transient measurements of Si/MoS2 heterojunction under the modulated light reveal that the devices can function up to 50 kHz. The Si/MoS2 heterojunction is found to be sensitive to broadband wavelengths ranging from visible to near-infrared light with maximum detectivity up to ≈1.4 × 1012 Jones (2 V bias). Reproducible low dark current and high responsivity from over 20 devices in the same wafer has been measured. Additionally, the MoS2/Si photodetectors exhibit excellent stability in ambient atmosphere.
Highlights
Two-dimensional molybdenum disulfide (MoS2) is a promising material for ultrasensitive photodetector owing to its favourable band gap and high absorption coefficient
We report Si/MoS2 (p-n) heterojunction based photodetector contrived from a very simple, reproducible and scalable fabrication process
It is likely that these stratified features in the MoS2 thin film formed as a result of the difference in the thermal expansion coefficient of substrate and the MoS2 film during sulfurization
Summary
Two-dimensional molybdenum disulfide (MoS2) is a promising material for ultrasensitive photodetector owing to its favourable band gap and high absorption coefficient. We report Si/MoS2 (p-n) heterojunction based photodetector contrived from a very simple, reproducible and scalable fabrication process. The high asymmetry observed in the I–V characteristics clearly indicates the formation of a very good p-n junction between the n-type MoS2 and p-type Si. A dark current of ~1.8 × 10−7was measured at reverse bias of 3 V, which enhances ~127 times upon illumination under 560 nm light of intensity 5 mW/cm[2].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
