UV Light Detection from CdS Nanocrystal Sensitized Graphene Photodetectors at kHz Frequencies

TL;DR

This paper presents UV photodetectors using CdS nanocrystals and graphene, achieving kHz frequency detection through enhanced light absorption and charge transfer mechanisms despite slow charge relaxation.

Contribution

It introduces a hybrid CdS nanocrystal-graphene photodetector with high responsivity and fast pulse detection capabilities at kHz frequencies, supported by time-resolved analysis.

Findings

High responsivity UV detection achieved

Detection of pulses up to 2 kHz frequency

Insights into charge transfer mechanisms

Abstract

We have fabricated UV-sensitive photodetectors based on colloidal CdS nanocrystals and graphene. The nanocrystals act as a sensitizer layer that improves light harvesting leading to high responsivity of the detector. Despite the slow relaxation of the photogenerated charges in the nanocrystal film, faster processes allowed to detect pulses up to a repetition rate of 2 kHz. We have performed time-resolved analysis of the processes occurring in our hybrid system, and discuss possible photo-induced charge transfer mechanisms.