Sensors that detect variations in the surroundings and convert them into
electrical signals are crucial in numerous fields, including healthcare, manufacturing,
and environmental monitoring. Optical sensors, in terms of various sensing principles,
hold considerable potential due to their fast response, high sensing resolution, and
ability to withstand magnetic interference. Despite their advantages, traditional optical
sensing techniques also have certain limitations, such as bulky structures, tedious
alignment procedures, and high production expenses. To address this issue, on-chip
integration has been proposed, and GaN and its alloys can be ideal materials due to
their high efficiency, long lifespan, and high stability. By simultaneously forming the
light emitter and photodetector on a shared substrate through wafer-fabrication
processes, miniaturized GaN optical sensors possess a compact design, small size, high
robustness, low manufacturing cost, and simple operations. This chapter discusses the
working mechanisms and influencing factors of integrated GaN devices alongside their
recent progress in advanced sensing applications.
Keywords: GaN, Integrated optical devices, Optical sensors, Sensing devices.
