Strongly coupled van der Waals heterostructures for high-performance infrared phototransistor

The interfacial coupling in van der Waals (vdWs) heterostructures can effectively modulate the device performance. In this study, we demonstrate a high performance infrared detector fabricated by direct epitaxial growth of Te nanowires onto a MoS₂ monolayer. Such directly grown Te/MoS₂ heterostructures show much stronger interfacial coupling than artificially transferred Te/MoS₂ hybrids, as evidenced from their Raman and photoluminescence spectra. The strong vdWs interfacial coupling leads to a high performance infrared detector with both ultrahigh photoresponsivity (>10³ A/W) and rapid response time (τ_rising = 15 ms) at the telecommunication wavelength of 1550 nm. The anti-bipolar and rectification behaviors observed in the strongly coupled grown Te-MoS₂ heterojunction further confirm the effective interfacial coupling. In contrast, the weakly coupled transferred Te-MoS₂ heterojunction that is obtained by artificial transfer exhibits negligible anti-bipolar behavior and slight rectification behavior. These findings indicate that the coupled vdWs hybrid structures have great potential for achieving high performance photodetectors.