New Frontiers in Band-Gap Engineering: Novel Alloys and Quantum Structures

David Wang Auditorium, 3rd floor Dalia Maydan Bldg.
Dr. Asaf Albo

Dr. Asaf Albo
Research Laboratory of Electronics, Massachusetts Institute of Technology,

Contemporary band gap engineering can be expanded through the crystal growth of novel semiconductor materials. The incorporation of additive atoms to conventional semiconductor alloys is suggested as an efficient strategy to extend their functionality and design flexibility of devices. As an example for this approach, I will review my contributions on MOCVD growth of mixed-anion III-V-N (dilute-nitrides) alloys and demonstrate the increased flexibility that was achieved in designing novel quantum structures and devices. I will present also the high potential of related novel III-N-As (dilute-arsenides) materials and quantum structures to solve key technological challenges in optoelectronics.

A further example of novel band gap engineering is by designing artificial superlattices. The extreme precision in semiconductor materials growth together with their high quality allows to further extend band-gap engineering to control not only the band gap across a device but also the electron dynamics and scattering processes. One of the greatest achievements using this approach is terahertz (ℏ~ 8 − 20 ) quantum cascade lasers (THz-QCLs) founded on designed electron dynamics in less than handful of subbands. As a demonstrative case study for this capability, I will review my efforts to untangle the complexity of the temperature driven electron transport in THz-QCLs towards extending their operation to room temperature (kBT~ 26 ).