Graphene Bilayer Field-Effect Phototransistor for Terahertz and Infrared Detection

TL;DR

This paper proposes and analyzes a graphene bilayer field-effect phototransistor capable of tunable spectral detection in the terahertz and infrared ranges, showing potential for superior photodetector performance.

Contribution

The study introduces a novel GBL-PT device model and demonstrates its voltage-tunable spectral characteristics and enhanced detection capabilities in the terahertz and infrared spectrum.

Findings

Spectral characteristics are voltage tunable.

Performance exceeds that of existing photodetectors.

Device model accurately predicts responsivity and detectivity.

Abstract

A graphene bilayer phototransistor (GBL-PT) is proposed and analyzed. The GBL-PT under consideration has the structure of a field-effect transistor with a GBL as the channel and the back and top gates. The positive bias of the back gate results in the formation of conducting source and drain sections in the channel, while the negatively biased top gate provides the potential barrier which is controlled by the charge of the photogenerated holes. The features of the GBL-PT operation are associated with the variations of both the potential distribution and the energy gap in different sections of the channel when the gate voltages and the charge in the barrier section change. Using the developed GBL-PT device model, the spectral characteristics, dark current, responsivity and detectivity are calculated as functions of the applied voltages, energy of incident photons, intensity of electron and hole scattering, and geometrical parameters. It is shown that the GBL-PT spectral characteristics are voltage tuned. The GBL-PT performance as photodetector in the terahertz and infrared photodetectors can markedly exceed the performance of other photodetectors.