Excitonic switches operating at around 100 K

Photonic and optoelectronic devices may offer the opportunity to realize efficient signal processing at speeds higher than in conventional electronic devices. Switches form the building blocks for circuits, and fast photonic switches have been realized(1-6). Recently, a proof of principle demonstration of exciton optoelectronic devices was reported(7,8). The potential advantages of excitonic devices include high operation and interconnection speed, small dimensions and the opportunity to combine many elements into integrated circuits. Here, we demonstrate experimental proof of principle for the operation of excitonic switching devices at temperatures around 100 K. The devices are based on an AlAs/GaAs coupled quantum well structure and include the exciton optoelectronic transistor (EXOT), the excitonic bridge modulator (EXBM), and the excitonic pinch-off modulator (EXPOM). A two orders of magnitude increase in the operation temperature compared to earlier devices (1.5 K; refs 7,8) is achieved.