Effect of nonuniform current injection on electroluminescence spectra of InGaN-GaN blue-green light-emitting diode

Blue-green InGaN/GaN light-emitting diodes (LEDs) with spatially nonuniform current injection were fabricated and tested. Broad electroluminescence (EL) spectra with equal peak intensities of blue and green emission lines and shallow trough between them were observed at elevated injected current. These features of EL-spectrum are believed to be caused by the mesh-like patterning of the electrode as it creates spatially nonuniform electric potential which provides spatial modulation of the injected current along the QW-planes. The latter results not only in spatial nonuniformity of intensity of generated light along the QW-planes but due to screening of polarization field in the QWs causes also position-dependent blue shift of EL. The observed phenomenon can be used to control the EL spectra of dual-wavelength LEDs by the patterned electrodes.