Photosensitivity enhancement in Cu2O based visible light photodetector: the effect of Eu(III)

Abstract

Cu₂O films were electrochemically deposited on FTO glasses, and the simplest solid-state structures were prepared by the formation of silver contact on the surface of Cu₂O film. Addition of europium nitrate to the electrodeposition electrolyte results in a few time increase of the responsivity of FTO/Cu₂O/Ag structures both in the photodiode (without application of an external bias voltage) and photoresistor (with an external bias voltage) operation modes. In particular, in the self-powered mode, the photodetector prepared with the addition of Eu(III) to the electrolyte demonstrates 4-fold increase in the ampere-watt responsivity reaching 6.7 mA/W at 589 nm. At an external bias of 2 V, the ampere-watt responsivity and specific detectivity under 525 nm illumination for the Eu-modified film-based photodetector are 87.2 A/W (18-fold increase) and 3.11∙10¹² cm∙Hz^0.5/W (6-fold increase), respectively. The increase in photosensitivity is explained by the suppression of charge carrier recombination in the films prepared with the addition of europium, which is confirmed by the photoluminescence spectroscopy.

Graphical abstract