Highly Sensitive Ti₃C₂Tx/MoSe₂ (2-D/Quasi-2-D) Heterojunction-Based Photodetector

Two-dimensional materials, which can be synthesized using low-temperature methods such as liquid exfoliation, are now being considered for electronics and optoelectronics applications due to their unique optoelectronic properties and ability to be processed into various structures. In this article, a 2-D material, i.e., Ti3C2Tx/MoSe2 with a nanometer-thick Ti3C2Tx MXene and MoSe2 film, has been fabricated by a successive interfacial assembly of liquid exfoliated 2-D MXene and MoSe2 over SiO2 substrate. Photodetectors (PDs) made of Ti3C2Tx/MoSe2 over SiO2 on Si substrate exhibit significantly improved photodetection ability. The photoresponsivity of Ti3C2Tx/MoSe2 PD is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim {{159} ~\text {mA}/{0}}$ </tex-math></inline-formula> when illuminated by a 372-nm light intensity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.4~\mu $ </tex-math></inline-formula>W at a reverse bias of −1.5 V. The interface between the 2-D and quasi-2-D effect on the formation of the heterostructure played a major role in the enhancement of its photodetection performance. The observation of high responsivity <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim {{159}~\text {mA}/\text {W}}$ </tex-math></inline-formula>, as well as external quantum efficiency (EQE) (53%) for Ti3C2Tx/MoSe2 PD, makes it a promising material for a UV light photoswitch and image sensors. This work sheds light on the utilization of a combination of 2-D MXene and quasi-2-D MoSe2 materials in high-performance optoelectronic devices.