Surface 210 nm light emission from an AlN p-n junction light-emitting diode enhanced by A-plane growth orientation

(11(2) over bar 0) A-plane AlN p-n junction light-emitting diode (LED) with a wavelength of 210 nm is demonstrated. The electroluminescence from the A-plane LED is inherently polarized for the electric field parallel to the [0001] c-axis due to a negative crystal-field splitting energy. The polarization ratio (electric-field component ratio of parallel and perpendicular to c-axis) is as high as 0.9. The radiation pattern of the A-plane LED shows higher emission intensity along the surface normal, while that of a conventional (0001) C-plane LED shows lower emission intensity along the surface normal. The different radiation patterns can be explained by the polarization property. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3446834]