Fully GaN Monolithic Integrated Light Emitting Triode‐on‐Bipolar Junction Transistor Device Drivable with Small Current Signals and Its Frequency Response Characteristic: A Modeling and Simulation Study

Intelligent display with multifunctional integration is becoming the frontier and focus of current research on novel display technology. How to realize the single chip integration of lighting with other functions such as switching and driving remain the technical and scientific problems that are desiderated to solve. This article proposes a novel idea of a light‐emitting triode (LET), in which light‐emitting diode (LED) and bipolar junction transistor (BJT) are vertically integrated on a single GaN chip with the same GaN processing. The photoelectrical performances of this “LED on BJT” structure are investigated using finite element simulation. It is verified that LET with electrical–optical modulation and amplification capabilities could be achieved simultaneously. By optimizing the device structure and the doping concentrations of each epitaxial layers, the LET can be operated at a low modulation current injection in the range of tens of microamperes. Therefore, the LET is expected to be directly driven by IC circuits without additional amplifier circuits. Meanwhile, the LET cut‐off frequency can reach more than 80 MHz, allowing the applications of pulse width modulation (PWM) driving and visible light communications.