Boosting Phototransistor Performance in Monolayer TMDs via Multiple Reflections from DBR

Transition-metal dichalcogenides (TMDs) are intensively studied for high-performance phototransistors. However, the device performance is limited by the single photoexcitation. Here, we show a unique strategy in which phototransistor performance can be boosted by fabricating the device on top of a distributed Bragg reflector (DBR). Monolayer molybdenum disulfide (MoS2) and tungsten disulfide (WS2) phototransistors were fabricated on DBR and SiO2 substrates for comparison. Furthermore, phototransistor performances including photocurrent, responsivity, photoinduced mobility, and subthreshold swing highlight 582 times enhancement in photoresponsivity ratio and 350 times enhancement in photocurrent ratio in the DBR sample using transparent graphene electrode and hBN encapsulation.

Automated summary

Researchers have shown that the performance of transition-metal dichalcogenides phototransistors can be improved by fabricating the device on top of a distributed Bragg reflector (DBR). The DBR sample exhibited a significant enhancement in photoresponsivity ratio and photocurrent ratio compared to the SiO2 substrate sample, with transparent graphene electrode and hBN encapsulation.