THz electroluminescence from Si/SiGe quantum cascade heterostructures

Summary form only given. THz electroluminescence from a Si/SiGe quantum cascade structure operating significantly above liquid helium temperatures was demonstrated. The band structure was engineered to give surface normal emission utilising a light-hole (LH) to heavy-hole (HH) valence intersubband transition. Samples were grown by low-pressure chemical vapour deposition on a strain relaxed SiGe buffer. The epitaxial layer thickness of the structure and Ge mole-fraction were characterised by transmission electron microscopy (TEM), energy filtered TEM (EFTEM) and energy dispersive X-rays (XRD). The results are promising for the development of an electrically pumped silicon based THz quantum cascade laser operating at liquid nitrogen temperatures.