High-performance photodetectors based on band alignment of type-I Te/WSe2 and type-III Te/ReS2 van der Waals heterostructures

Abstract

Quasi-2D tellurium (Te) shows promise in optoelectronics, but multilayer Te has high dark current. We've improved Te photodetectors by combining 2D Te with transition metal dichalcogenides (TMDs) like WSe2 and ReS2. Te FETs are p-type with a peak mobility of 540 cm2V−1s−1, responsive to a wide wavelength range (532–1064 nm). Te/WSe2 has Type-I band alignment, with a high 60 mA/W responsivity and fast response times (5.6 μs rising, 9.5 μs decaying). Te/ReS2 offers Type-III band alignment and excels at positive bias voltage, with a 141.48 A/W responsivity. These findings enhance Te's versatility in electronics and optoelectronics.