Physics Chat
Multimodal micro-spectroscopy characterisation of III-nitride light emitters for next generation lighting sources
Speaker: Kimberly Nicholson ()
Date: Wednesday 19 March 2025
Time: 14:00
Venue: N/1.32
InGaN-based LEDs grown on Si have transformed lighting industry, estimated to be worth USD 81.48 billion1 and are gaining interest for full-colour displays. However, a vital challenge for the epitaxial growth of InGaN-based long-wavelength LEDs (green and red)2 on Si is strain management where various strategies such as buffer layers and InGaN interlayer have been implemented to suppress strain within the epilayers. GaN has also gained attention as a promising material for single photon emitters (SPE), a core element for quantum computing, though the origin of SPE remains unclear. Here we implement, scanning electron microscopy (SEM)-based techniques, electron channelling contrast imaging (ECCI) to determine dislocation density3 formed during growth and investigate the possibility of using cathodoluminescence (CL) as a technique for identifying SPE. These rapid non-destructive SEM-based techniques are correlated with Raman spectroscopy and XRD to determine the crystal quality, estimate the dislocation density and investigate the stress/strain formed within the epilayers. Rapid and non-destructive characterisation methodology is therefore crucial to swiftly provide feedback to growth in the supply chain forming the basis of full-wafer scale characterisation methodology.
[1] Grand View Research, Market Analysis Report, LED Lighting Market Size & Trends [2] Usman et al., Critical Reviews in Solid State and Materials Sciences, 46, 450 (2020) [3] Naresh-Kumar et al., Phys. Rev. Lett. 108, 135503 (2012).