The accurate measurement and determination of key parameters are imperative for improving the performance of light-emitting diodes (LEDs). Among these key parameters, the internal quantum efficiency (IQE) describes the efficiency of the radiative recombination within the active region of an LED structure. Since the IQE is independent of device processing and depends purely on material quality and active region design, it provides an important metric to optimize material growth processes. The main technique to investigate the IQE, without creating a full device is based on (time-resolved) photoluminescence (PL). However, due to the limited achievable spatial resolution of PL, its application towards micro-LEDs and optical nanostructures is strongly limited. Cathodoluminescence (CL) has emerged as a promising alternative to PL due to its higher spatial resolution and ability to easily excite wide bandgap semiconductors. However, using cathodoluminescence for IQE determination is still a mostly unexplored application. Specifically, the lack of resonant excitation and the low control over the injected carrier densities limit the transfer of most established PL based IQE measurement techniques. This leaves time-resolved techniques to be explored for IQE determination with CL.
The aim of my master project is to develop methods to determine the internal quantum efficiency (IQE) and its local variations of quantum wells in wide bandgap AlxGa1-xN using time resolved cathodoluminescence spectroscopy (CL). My work initially involves both continuous wave measurements and temperature-dependent time-resolved CL measurements on micro platelet based relaxed micro-LED structures emitting in the UV-B and UV-C spectral range. In the later stage, I will extend these studies to other structures to make a thorough analysis of the carrier lifetime and IQE for future growth optimization with a specific focus on how different defect types impact device efficiency.
I completed my BSc in Physics at Peking University and conducted short-term research projects at the Amano–Honda Laboratory at Nagoya University during my undergraduate years. I joined the group as a research MPhil student in October 2025. My previous research experiences include GaN-based laser diodes, compositionally graded AlGaN FinFETs, and ohmic contacts for p-type GaN. Outside the lab, I enjoy photography, bodybuilding, creative cooking and baking.
