1-2 ML thick InN-based quantum wells with InGaN barriers for blue-green light emitters

An LED structure with a 1-2 monolayer (ML) thick InN quantum well (QW) with InGaN barrier grown by radio-frequency plasma assisted molecular beam epitaxy (rf-MBE) is proposed for a new active layer of blue-green light emitters. Compared with previously reported 1-2 ML thick InN/GaN QWs, extended emission wavelength up to pure green region (similar to 530 nm) is expected for these QWs with InGaN barriers. It is found that for the InN/InGaN QW structure, in which the InGaN layer is used as a barrier instead of GaN, very thin InN well layers are basically formed in the same manner as the InN/GaN QWs. In photoluminescence spectra at 15 K, emission peak wavelengths are observed from 412 nm to 480 nm when In contents in InGaN barriers are changed from 0.005 to 0.14. The emission wavelength is longer than that of 1-2ML thick InN/GaN QWs (380nm-430nm), and green emission can be obtained by further increase of In content in InGaN barrier to more than 0.2. The 12 ML thick InN/In(0.08)Ga(0.92)N(10nm) 5-QW LED structure was successfully fabricated and bright EL emission was observed at 419 nm, which is longer than that of a 1-2 ML InN/GaN 5-QW LED. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim