Background:
III-nitride semiconductors (AlN, GaN and InN) have been considered promising materials for photonic, high power and high temperature electronic devices. Compared to other most commonly used semiconductors, III-nitrides have good peak electron velocity, large breakdown voltage, and high thermal heat conductivity, which are important parameters for electrical and optical devices. This is confirmed by very high output power at high frequencies that have been obtained for heterostructure field effect transistors (HEMT) based on a structure where a less than 30 nm thick AlGaN grown on top of bulk GaN. Due to the large conduction band offset and high polarization, a two-dimensional electron gas (2DEG) is formed at the AlGaN/GaN interface.
Task:
In this project, the relation between the depth (from the surface) and the electron concentration of the 2DEG in the AlGaN/GaN heterostructure will be studied. Other factors, such as the AlGaN thickness, the Al-composition in AlGaN, and Si doping in the AlGaN layer, will also be investigated by Hall-effect measurements and capacitance-voltage (CV) profiling.
Contact persons:
Thorvald Andersson,
(thorvald.andersson@mc2.chalmers.se)
Xinyu Liu