Nanostructured doping of WSe block copolymer patterns and its self-powered photodetector application.

Transition metal dichalcogenides (TMDs), , MoS, MoSe, ReS, and WSe, are effective materials for advanced optoelectronics owing to their intriguing optical, structural, and electrical properties. Various approaches for manipulating the surface of the TMDs have been suggested to unleash the optoelectronic potential of the TMDs. Herein, we employed the self-assembly of the poly(styrene--methyl methacrylate) (PS--PMMA) block copolymer (BCP) to prepare a nanoporous pattern and generate nanostructured charge-transfer p-doping on the WSe surface, maximizing the depletion region in the absorber layer. After the spin coating and thermal annealing of PS--PMMA, followed by the selective etching of PMMA cylindrical microdomains using oxygen reactive-ion plasma, nanopatterned WO with high electron affinity was grown on the WSe surface, forming a three-dimensional homojunction. The nanopatterned WO significantly expanded the depletion region in the WSe layer, thus enhancing optoelectronic performance and self-powered photodetection. The proposed approach based on the nanostructured doping of the TMDs BCP nanolithography can help create a promising platform for highly functional optoelectrical devices.