Improved optical performance in near visible light detection photosensor based on TFET

Abstract

This paper presents the performance comparison of Si-based, Ge-source, and Heterogate (HG) TFET photosensor under visible range of spectrum using TCAD simulator. The optical generation rate, energy band diagram, Band to Band Tunneling rate, and electron density contour have been plotted for TFET based sensor under both light and dark regimes to investigate their optical behavior. Furthermore, spectral sensitivity (Sn) graph is extracted as a function of wavelength (λ) and gate voltage (Vgs) for these photosensors. Due to increased tunneling rate of optically produced carrier along the channel, the Sn of HG-TFET photosensor is found higher compared to Ge source and Si-based TFET photosensors. The Signal to Noise Ratio (SNR), Responsivity (R), and quantum efficiency (η) are reported to examine the performance of these photosensors in more elaborately. It is seen that the HG-TFET photosensor exhibits a better noise immunity and Responsivity rate relative to other simulated photosensing device. Finally, the various performance metrics of these photosensors are compared in tabular form. It is found that HG-TFET based photosensor has superior optical performance and its performance is further analyzed using Ge source or HfO2 as gate dielectric material.