Heat generation and dissipation in GaN-based light emitting devices

InGaN laser diodes were been grown by metalorganic vapor phase depositions on sapphire substrates. These lasers were processed as gain guided structures and showed lasing in pulsed mode operation with duty cycles up to 2% at a wavelength of 401 nm. We determined the activation energy of the carriers in the active region by temperature dependent electroluminescence measurements during LED operation. By this means we estimated the temperature evolution inside the quantum wells by recording the transients of the output intensity during a single pulse. To verify the correlation of light output power and heating of the active region we performed simulations of the heat distribution in laser diodes on a two-dimensional mesh, which contained the laser structure including the substrate. With the help of these simulations we were able to reconstructed the temperature evolution within the active region in good agreement with the experiment and determined the heat generation to be the limiting factor of the lasers driving conditions. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)