The article discusses the simulation of an nBn-InGaAs photodetector using Silvaco TCAD at 300 K, focusing on optimizing the barrier performance and reducing the valence band offset. It explores the device’s electrical and optical behaviors, including dark current, photocurrent, and capacitance. The results show a peak responsivity of 0.91 A/W at 1.55 µm and a junction capacitance of 9 pF at −5 V. Adding an anti-reflection coating notably improved the optical performance, highlighting the structure’s potential for efficient infrared photodetection.