Improved optical performance of a photo-gated tunnel FET with hetero-dielectric and PNPN configuration

This manuscript provides a comprehensive comparative analysis of photoresponse characteristics of conventional PIN Tunnel Field-Effect Transistors (TFETs) and hetero-dielectric PNPN TFET (HD-PNPN TFET) photodetectors operating within the visible light spectrum (400 to 700 nm), utilizing Sentaurus TCAD simulations. Key performance parameters including sensitivity, light-to-dark current ratio (LDCR), responsivity, and detectivity are assessed under both illuminated and dark conditions with an n-type silicon-based optical gate. The impact of visible light on the optical gate is examined by analyzing photogeneration and energy band under various illumination conditions. Simulation results demonstrate that the HD-PNPN TFET achieves superior optical performance, with a maximum sensitivity of 10 . 28 × 1 0 5 and an LDCR of 210 dB in the subthreshold regime, as well as optimal performance in the superthreshold regime. Additionally, the device exhibits enhanced responsivity of 7 . 78 × 1 0 3 A/W and detectivity of 4 . 9 × 1 0 10 Jones when compared to the conventional PIN-TFET. The device also shows high external quantum efficiency, indicating effective photon-to-charge carrier conversion. Further investigations explore the effects of gate dielectric materials, insulator BOX composition, interface trap charges, and temperature on the parameters like sensitivity and LDCR. The use of a hetero-dielectric gate-oxide and high- k BOX material results in improved optical performance, while interface trap charges and temperature have minimal influence on the performance of HD-PNPN TFET. A detailed tabular comparison confirms that the HD-PNPN TFET significantly surpasses the conventional design across all key optical metrics. • Novel HD-PNPN-TFET photosensor with high- k dielectric BOX simulated using Sentaurus TCAD. • N + pocket enables sharp tunneling junction, improves BTBT efficiency. • Hetero dielectric enhances control, yielding high I ON and low leakage. • Shows 128 sensitivity and 42.2 dB LDCR compared to PIN photosensor. • Achieves 7.96×10 4 EQE and 4.53×10 10 Jones detectivity for weak signals.