384 nm laser diode grown on a (202¯1) semipolar relaxed AlGaN buffer layer

We demonstrate an electrically injected semipolar (202¯1) laser diode grown on a partially relaxed AlGaN buffer layer. The coherency stresses are relaxed by misfit dislocations at the GaN/AlGaN heterointerface which form by glide of preexisting threading dislocations along the (0001) basal plane. The defects are confined to the heterointerface which allows the growth of high aluminum composition films with threading dislocation densities of less than 108 cm−2. The lasing wavelength was 384 nm with a threshold current density of 15.7 kA/cm−2. UV lasers grown on semipolar relaxed AlGaN buffers provide an alternative to devices grown on AlN or sapphire.