Blue laser diodes by low temperature plasma assisted MBE

Recent progress in the growth of nitride based semiconductor structures made by plasma assisted MBE (PAMBE) is reported. The technology is ammonia free and the nitrogen for growth is activated by an RF plasma source from nitrogen molecules. A new approach for the growth of nitrides by PAMBE at temperature range 500 - 600 degrees C is described. The key for this technique is to use a thin, dynamically stable metal (In or Ga) layer on the (0001) GaN surface, which enables a high quality 2D step-flow growth mode to be achieved at temperatures much lower than those determined by thermodynamic considerations. A new perspective for PAMBE in optoelectronics has been opened recently by a demonstration of continuous wave operation of InGaN blue-violet laser diodes. These laser diodes were fabricated on bulk GaN substrates with a low threading dislocation density.