Material and illumination model optimization of OPFET for visible light communication

Abstract

Through material and illumination model optimization, we seek to investigate the potential of enhancing the performance of Optical Field Effect Transistor (OPFET)-based detector-cum-amplifier in Visible Light Communication (VLC) applications. This paper studies Si, InP, and GaAs materials and the buried-gate front-illuminated and generalized OPFET models. The detector metrics namely responsivity, 3-dB bandwidth, Signal-to-Noise Ratio, and the unity-gain cut-off frequency have been calculated. The results of the study confirm that on the whole, the generalized model has superior bandwidth performance to the buried-gate and back-illuminated models under low background lighting communication applications. GaAs generalized OPFET shows the largest detection/amplification bandwidth of 68.4/22.2 GHz at an intensity of 1019 /m2-s with a responsivity of 1×107 A/W. The findings point to potential use in VLC applications involving data rates of 100 Gb/s and above. Under high background lighting conditions, at an intensity of 1022 /m2-s, the InP generalized model exhibits the highest combined bandwidth of 22.1 MHz and a responsivity of 9.6×103 A/W. The detectors show Signal-to-Noise ratios exceeding 200 dB. The GaAs OPFETs exhibit a maximum 3 dB-cum-amplification bandwidth in the far gigahertz range, while the InP OPFET in the near gigahertz range, and the Si OPFET in the near megahertz range. These three OPFETs have applications respectively in high, medium, and low data rate VLC. All the device models exhibit significantly high responsivities. The results have been analyzed for photoconductive, photovoltaic, and series resistance effects. They provide the basis for further research.