Interconnect‐Integrated GaInP/AlGaAs Schottky Photodetector Array with Heterojunction‐Assisted Enhanced Photovoltaic Effect for Automotive Speed Measurement Systems

Abstract

AbstractReducing power consumption has always been a pressing issue for integrated circuits. Currently, there is a strong interest in the development of self‐powered photodetectors with low power consumption, high quantum efficiency, and high integration. In this work, a novel GaInP/AlGaAs photodetector is developed, where the photovoltaic effect of the Schottky junction is enhanced by the assistance of underneath GaInP/AlGaAs heterojunction, achieving near unity quantum efficiency, high integration, and ultrafast response speed. A single device exhibits a responsivity (R) of 467 mA W−1 in photovoltaic mode, a specific detectivity (D*) of 1.43 × 1011 Jones, a power conversion efficiency (PCE) of 14.5%, and an external quantum efficiency (EQE) of 96.56%. Further, an interconnect integration technique is used to integrate 81 individual detector units onto a 5 × 5 mm2 chip, resulting in a detector array that significantly improves the optical response. The device array has a high frequency feature with a fast response of 19 µs and a −3 dB bandwidth of 21.34 kHz. The interconnect chip is further integrated with a STM32 chip to realize an automotive speed measurement system. This work provides a novel technological solution for a high‐frequency, highly integrated photodetector array using heterojunction‐assisted enhanced GaInP Schottky junctions.