III-Nitride Microsensors for 360° Angle Detection

The fabrication of a miniature III-nitride angle sensor is demonstrated. A monolithic device composed of a light emitter and four detectors is fabricated on a GaN-on-sapphire wafer. By integrating the device with a glass cylindrical container partially filled with ethanol as a liquid pendulum, the on-chip detectors can effectively sense the change of internally reflected light with angle rotation, and produce the photocurrent signals to indicate the angle level. Verified by a series of experimental measurements, the millimeter-sized sensor exhibits full-angle detection capability, sub-second response time, and high repeatability, which makes it well suited for broad practical applications in angle sensing.