An optoelectronic band-to-band tunnel transistor for near-infrared sensing applications: Device physics, modeling, and simulation

Abstract

In this article, we propose a novel optoelectronic band-to-band tunnel field effect transistor with a Si photo-gate, for multi-spectral sensing of near-infrared light in the wavelength range of 0.7 μm–1 μm. Based on the line tunneling approach, a drain current model has been developed to illustrate the device operating principle. The model incorporates the effect of photo-generation in the photo-gate in terms of the resulting photo-voltage. Good agreement with device simulation results indicates overall correctness of the developed model. The spectral response of the device has been studied in terms of its input and output characteristics, and the spectral sensitivity has been defined in terms of the change in current, in response to the change in the illumination wavelength. The proposed device can resolute closely spaced spectral lines (∼100 nm) in the wavelength range of 0.7 μm–1 μm, due to the combined effects of steep average sub-threshold swing of ∼19 mV/dec, over five current decades, and current modulation due to change in the tunnel path length, induced by the gating effect of the photo-generated carriers. Peak spectral sensitivity at an illumination intensity of 0.5 W/cm−2 is found to be 5.88 × 103, 2.14 × 103, and 3.56 × 102 corresponding to decrease in illumination wavelength from (1 μm to 0.9 μm), (0.9 μm to 0.8 μm), and (0.8 μm to 0.7 μm), respectively. The influence of different device parameters, on the spectral sensing performance of the device, is thoroughly investigated by TCAD simulations and through the developed model.