Brilliant photoluminescence from GaN film grown by PLD under particle-energy-manipulation

Epitaxial GaN films were deposited on (0 0 0 1) sapphire by the pulsed laser deposition (PLD) method using the ArF excimer laser and molten Ga target. Prior to the growth experiment, we measured the ablated Ga dynamics from the plume motion with the help of the ultra high speed framing streak camera, and obtained the intrinsic parameters of Ga ablation, such as the mean drift energy as high as 29 eV. This excessively high energy of the plume brought about damage into the film during the growth. To prevent this, the appropriate energy control of Ga particle was performed in two ways: one was an oblique incidence of the Ga plume, and the other was the deposition in the high N2 pressure ambient. Both made feasible to obtain the band edge emission (364 nm) of room temperature photoluminescence (PL).