In-situ photo-luminescence of growing III-Nitride LED structures
Laytec, which makes in-situ metrology tools for LED, laser and thin-film production, and Dirk Rueter 's group at University of Applied Sciences Ruhr West have reported a breakthrough regarding real-time monitoring of InGaN/GaN quantum well emission wavelength during MOCVD growth.
In this collaborative project, the researchers reported the first quasi-continuous in-situ photoluminescence study of growing InGaN LED structures inside an industrial-grade MOVPE reactor at growth temperature.
It is well known that room temperature wafer based photoluminescence (PL) measurements can be used to predict the emission wavelength and emission intensity of the later LED devices at room temperature. In this joint project, a prototype in-situ PL system worked simultaneously with a LayTec Pyro 400 (a production line in-situ metrology tool for monitoring real GaN surface temperatures in MOCVD systems) in a commercial multi-wafer MOCVD reactor.
The team demonstrated an accuracy of this predicted wavelength in the range of Â± 1.3nm (2 Ïƒ). It believes the technique is therefore suitable for closed-loop control of the emission wavelength of InGaN LEDs already during growth.
The work is supported under grant KF3242801NT3 by BMWi (German Federal Government).
'In-situ photoluminescence measurements during MOVPE growth of GaN and InGaN MQW structures' by C. Prall et al. Journal of Crystal Growth 415 (2015).