Bi2Te2Se and Sb2Te3 heterostructure based photodetectors with high responsivity and broadband photoresponse: experimental and theoretical analysis

Se heterostructure shows metallic behaviour. For the optical properties, the dielectric function's real and imaginary parts are calculated using DFT and random phase approximation (RPA). It is observed that these topological materials and their heterostructure are light absorbers in a broadband range, with maximum absorption at 1.90, 2.40, and 3.21 eV.