Research Fellows Directory
Dr Huiyun Liu
University College London
Si microelectronics has been the engine of the modern information for almost 50 years. In our everlasting quest to process more and more data at faster speeds, while using the smallest components the $100 billion silicon industry has successfully overcome many critical issues. The next critical problem in the evolution of modern information system is to overcome the limitations of metal interconnects. Incorporating photonic components into silicon microelectronics has the potential to overcome this issue while pushing forward the silicon microelectronics beyond the classical CMOS era.
Although Si-based light generation and modulation technologies have been explored extensively, their practicality has been severely limited due to the indirect bandgap of Si, the significant challenge posed by nature. Direct bandgap III-V compounds have robust photonic properties that can be tailored for III-V emitters operating at various wavelengths with high efficiency, large direct modulation bandwidth, and sufficient optical power output for many photonic applications. Integrating III-V photonic components with Si microelectronics would thus provide the ideal solution for Si photonics.
In my group at UCL, the III-V quantum dots – semiconductor nanosize crystal- have been used to develop III-V QD lasers on Si based on their special properties including low operating current and voltage, a high overall efficiency, stable operation at high temperature, and less sensitive to defects. During the last year, continuous-wave quantum-dot lasers on silicon substrates with low room-temperature threshold current density have been first demonstrated at UCL, which paths a way for the long-dreamed III-V/Si integration.
In addition, by combining low-cost silicon substrates and high-efficiency III-V solar cells, we developed III-V nanowire solar cells grown on silicon substrates with record high efficiency for nanowire solar cells grown on silicon substrates.
Interests and expertise (Subject groups)