Research activities of Koung-An Chao in 2002

The Lund Partner is corrently working on three projects within the scope of the Network activities. The first one is in the area of solid state power generation and cooling. These two processes are reversal to each other, so let us describe our work for cooling. In conventional approach, the heat removal is via contact to reservoir, which is very slow. Our breakthrough is to use both electrons and holes to carry the heat from opposite ends to the center, where they recombine and emit the heat in the form of light. We call this optothermionic process. Since we published our work, there has been much response from industries.

The second project is spin polarized transport in III-V semiconductor heterostructures. Our spintronic system is "All semiconductor", which has semiconductor injector, semiconductor barrier, and semiconductor transport channel. This novel system does not include any magnetic element, and its operation is based on the strong spin-orbit interaction in III-V compounds. Consequently, when the device operates at room temperature, it still has about 10 percents spin polarization.

The third project is impurity level structure in modulation doped semicnductor heterostructures. An ab-initia scheme of calculation is proposed to derive all impurity-related energy levels as well as their life times. The results of this calculation point out a new way to construct Si-based THz lasers using only conduction electrons.
Gerlinde Xander