A Darlington Transistor Using Cascaded n-p-n Light-Emitting Transistors for Temperature Sensor Applications

The advent of Light-Emitting Transistors (LETs) represents a groundbreaking advancement in the realm of optoelectronics, achieved through the incorporation of quantum-wells (QWs) into the base of heterojunction bipolar transistors (HBTs) [1] – [2] . The QW serves as a reservoir for capturing electrons as they transport from the emitter to the collector. As the temperature rises, electrons gain the sufficient energy to overcome the QW barrier, ultimately reaching the collector terminal and contributing to the collector current. Consequently, both the collector current (I C ) and current gain (β=ΔI C /ΔI B ) experience increase [3] – [4] . Notably, the collector current exhibits high sensitivity to temperature variations. To further enhance the current sensitivity and collector current, a strategic approach involves cascading two n-p-n LETs in a Darlington transistor configuration. In this study, we present a demonstration of the thermally induced collector current enhancement in a Darlington transistor utilizing cascaded staircase-QW LETs.