A three-terminal light emitting and detecting diode

Two-terminal devices are building blocks for modern electronic systems. However, the typical two-terminal architecture can limit functionality and performance. Here we report a multifunctional three-terminal diode that consists of a traditional two-terminal gallium nitride-based p‒n diode with a monolithically integrated third terminal (Tt) composed of metal/Al2O3 dielectric layer directly on the p-layer. When the three-terminal diode operates as an emitter, the light intensity can be tuned by adjusting the bias applied to the Tt, and its modulation bandwidth can be increased from 160 MHz in the original p‒n diode to 263 MHz due to the integrated bias tee function enabled by the Tt. When it operates as a photodetector, both the applied voltage on the Tt and the incident light act as signal inputs that control the magnitude of output photocurrent, providing reconfigurable optoelectronic NAND and NOR logic gates. By integrating a metal‒oxide‒semiconductor capacitor into a two-terminal diode, a multifunctional single device can be created that operates as a tunable light-emitting diode with a built-in bias tee circuit and a detector with a reconfigurable optoelectronic logic function.