High Power, Tunable Terahertz Sources Based on Intersubband Transitions in SIGE Quantum Wells.

摘要

Stepped quantum well structures in the SiGe-system make it possible to achieve tunable emission in the frequency range below 10 THz. The composition of these structures changes the emission frequency and the sensitivity towards changes of the applied field. The design of a stepped quantum well structure depends on the critical thickness for SiGe, the linearity of its characteristics and its behavior in a superlattice. We have successfully designed, fabricated and experimentally demonstrated the tunability of THz emission as a function of bias from SiGe quantum well devices. Increasing the bias current applied to the fabricated SiGe multiple quantum well device (from 250 mA to 550 mA) resulted in a change in emission frequency from 8.86 THz to 8.26 THz at 30K. This is a change of 7.2% infrequency and is close to the 10% tunability predicted.