Synthesis of high Al content Al Ga1−N ternary films by pulsed laser co-ablation of GaAs and Al targets assisted by nitrogen plasma

Composition and bandgap control of AlxGa1−xN films synthesized by plasma-assisted pulsed laser deposition

“…The Al composition in Al x Ga 1Àx N can also be adjusted by varying the laser fluence on the Al target. 20 The Al compositions in Al x Ga 1Àx N films B, C, and D were thus determined to be 0.11, 0.29 and 0.52, respectively, consistent with the EDXS results. It also seems that the incorporation of Al results in the degradation of the crystal structure, as suggested by the reduction in the diffraction intensity and the broadening in the diffraction width.…”

“…The equipment and the method used for sample preparation have been described previously, 20 except that the two laser beams were delivered using two frequency-doubled Q-switched Nd:YAG lasers which were controlled separately in the present work. In the environment of nitrogen plasma generated by ECR microwave discharge of pure (99.999%) N 2 gas using a 2.45 GHz microwave, a polycrystalline GaAs target and a metallic Al target were ablated simultaneously using two focused laser beams (wavelength: 532 nm; pulse width: 5 ns).…”

“…The Al composition in Al x Ga 1Àx N can also be adjusted by varying the laser fluence on the Al target. 20…”

“…19 We have previously demonstrated an alternative approach to the low-temperature synthesis of high Al composition ternary Al x Ga 1Àx N by pulsed laser co-ablation of a polycrystalline GaAs target and a metallic Al target with the assistance of nitrogen plasma generated by electron cyclotron resonance (ECR) microwave discharge of N 2 gas. 20 In the present work, the variation of the Al composition in Al x Ga 1Àx N and hence the bandgap modulation of Al x Ga 1Àx N were realized by simply varying the repetition rate of the laser pulses ablating the Al target. Compositional analysis, structural characterization and optical measurements were performed for the synthesized Al x Ga 1Àx N films having varied Al composition x and were compared with the corresponding characteristics of binary AlN (x = 1) and GaN (x = 0) films synthesized by single target ablation of Al or GaAs.…”