Dr Yihong Ji

Micro-displays require the development of highly efficient green, amber, and red-light emitting diodes (LEDs) at a few microns size, which remains extremely challenging for InGaN based micro-LEDs. For InGaN-based devices, the unsymmetrical structure of wurtzite GaN and large strain build up at InGaN/GaN interface often give rise to spontaneous and piezoelectric polarization, which will lead to band bending and reduce the overlap between the electron and hole wavefunctions and hence degrade the device light emission efficiency. I am currently working on two main routes to mitigate the above issue, which are the elimination of the spontaneous polarization by adopting the high symmetrical structure of cubic GaN and the reduction of piezoelectric polarization via strain relaxation by adopting a porous InGaN pseudo-substrate.