Efficient 230–280 nm emission from high-Al-content AlGaN-based multiquantum wells

We demonstrated efficient ultraviolet (UV) photoluminescence (PL) with the wavelength ranging from 230 to 280 nm from AlxGa1−xN(AlN)/AlyGa1−yN multiquantum wells (MQWs) grown on SiC by metalorganic vapor phase epitaxy. We systematically investigated the PL intensity of the AlGaN-based MQWs with wide-band-gap AlGaN barriers as functions of QW thickness and Al content of barriers. Single-peak, efficient PL emission was obtained at 282–234 nm at 77 K from AlxGa1−xN(AlN)/AlyGa1−yN 5-layer MQWs with approximately 1.5-nm-thick active layers by changing the Al content of the AlxGa1−xN barriers from 53% to 100%. The efficiency of the deep-UV emission from AlGaN-based QWs was as high as that of blue emission from InGaN-based QWs at 77 K.