Extremely high internal quantum efficiencies from AlGaN/AlN quantum wells emitting in the deep ultraviolet spectral region

AlGaN/AlN quantum wells (QWs) emitting at 247 nm grown by metalorganic vapor phase epitaxy. The extremely high IQEs were achieved by examining the source-supply sequence. QWs fabricated by a continuous source-supply method have longer emission wavelengths (lambda) and higher IQEs compared to QWs fabricated by modified migration enhanced epitaxy (MMEE). MMEE is an alternating source-supply method where the NH(3) interruption promotes Ga evaporation. Thus, to obtain the same lambda, MMEE requires a lower growth temperature than the continuous method, compromising the quality of the AlN and AlGaN layers as well as the IQE of QWs. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3607306]