AlGaN Quantum Well Heterostructures for Mid-Ultraviolet Emitters with Improved Room Temperature Quantum Efficiency
E.A. Shevchenkoa, A.A. Toropova, D.V. Nechaeva, V.N. Jmerika, T.V. Shubinaa, S.V. Ivanova, M.A. Yagovkinaa, G. Pozinab, J.P. Bergmanb and B. Monemarb
aIoffe Physical-Technical Institute, Russian Academy of Sciences, Polytekhnicheskaya 26, 194021 St. Petersburg, Russia
bDepartment of Physics, Chemistry and Biology, Linköping University, S-581 83 Linköping, Sweden
Full Text PDF
We report on optical studies of exciton localization and recombination kinetics in two single 2.2 nm thick AlxGa1-xN/Alx+0.1Ga0.9-xN quantum well structures (x=0.55 and 0.6) grown by plasma assisted molecular beam epitaxy on a c-sapphire substrate. Strong localization potential inherent for both the quantum well and barrier regions results in merging of the quantum well and barrier emission spectra into a single broad line centered at 285 nm (x=0.55) and 275 nm (x=0.6). Time-resolved photoluminescence measurements revealed surprising temperature stability of the photoluminescence decay time constant ( ≈ 400 ps) relevant to the recombination of the quantum well localized excitons. This observation implies nearly constant quantum efficiency of the quantum well emission in the whole range from 4.6 to 300 K.

DOI: 10.12693/APhysPolA.126.1140
PACS numbers: 78.67.De, 78.55.Cr, 71.35.-y, 78.66.-w