Band Fillling and Energy Relaxation in InGaN/GaN-Multiple Quantum Well Structures

✍ Scribed by T. Riemann; D. Rudloff; J. Christen; A. Krost; M. Lünenbürger; H. Protzmann; M. Heuken

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 233 KB
• Volume: 216
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/(sici)1521-3951(199911)216:1<301::aid-pssb301>3.0.co;2-j

✦ Synopsis

An InGaN/GaN multiple quantum well structure grown by low pressure MOCVD on c-Al 2 O 3 substrate is investigated using spectral-time-resolved cathodoluminescence microscopy (CL). At 6 K the laterally integrated CL spectrum shows a very efficient blue emission from the InGaN multiple quantum well centered at 2.841 eV with an FWHM of 50 meV (s = 21 meV). Spatially resolved CL wavelength mappings give a standard deviation of s = 7 meV for the InGaN peak position across an area of 55 Â 36 mm 2 . In time-resolved CL a strong monotonous redshift (DE = ± ±60 meV) of the main emission line is observed during 4.5 ms decay following the function E peak = E 0 ± ± 25 meV log (t/t 0 ) which is attributed to a thermalization of carriers within a statistically distribution of localized states. This is supported by a blueshift (DE = 75 meV) of the emission line upon increasing cw excitation power by three orders of magnitude (E peak = E 0 + 25 meV log (P/P 0 ).