Wide spectral response field effect phototransistor based on graphene-quantum dot hybrid

Abstract

The photoelectrical characteristics of field-effect phototransistors (FEPTs) are investigated experimentally based on a graphene–PbS quantum dot (QD) hybrid. The device presented a wide spectral response range from 300 to 1400 nm because of multiple-exciton generation of PbS QDs. The photoelectrical responsivity reached up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$2\times 10^{5}\ \hbox{A/W}$</tex-math></inline-formula> at low bias voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$\sim$</tex-math></inline-formula> 10 mV) and became more sensitive with increasing bias voltage. The transient response of the hybrid FEPTs was also measured with the relaxation times and the decay times around several seconds. Such devices exhibit great competitiveness in wide spectral response, flexible integrated circuits with low cost, large area, low energy consumption, and high responsivity.