Solution processed tellurium films for photodetection

Abstract

Single tellurium nanostructures are promising infrared photodetector materials. Despite advances, infrared photoresponsive devices relying on ensembles of tellurium nanoparticles have not emerged, notwithstanding the stronger absorption of light offered by ensembles of nanoparticles. Stronger light absorption is particularly desirable at infrared wavelengths, where most materials are only weakly absorbing. Here, we develop a new synthetic methodology that enables us to prepare photoresponsive tellurium films that comprise ensembles of nanoparticles. The structure of the resultant films is extensively characterized, and our studies reveal the existence of tellurium oxide as well as tellurium in these devices. Electrical characteristics of the devices prepared from these films show strong photoresponse to visible (404 nm, 532 nm) as well as infrared light (1550 nm) from wide area (2 mm × 2 mm) films of nanoparticles. Our results are consistent with the attainment of a passivating oxide layer that is beneficial for tellurium-based optoelectronics.