GaN Monolithic Optopairs for Rapid and High-Resolution Temperature Measurements

This article presents the fabrication and characterization of a gallium nitride (GaN)-based optopair for the temperature measurement. The monolithic device comprises a pair of indium gallium nitride (InGaN)/GaN multiquantum well diodes, enabling both light emission and detection functions. The device exhibits a monotonic increase in photocurrent response with increasing temperature, attributed to the increased spectral overlap between the emission and absorption. The developed device with a size of $1.1\times 1.3$ mm2 is capable of responding to changes in temperature range from $26.5~^{\circ }$ C to $150~^{\circ }$ C. With the advantages of fast response of less than 0.5 s, high resolution of $0.024~^{\circ }$ C, and compact structure, the proposed chip-scale design shows great potential in the field of high-precision, real-time temperature measurement.