A first-principles study of the effects of different Al constituents on Ga1−xAlxN nanowires

In order to investigate the influences of different Al constituents on Ga1−xAlxN nanowires, the formation energy, stability, band structure, densities of states and optical properties of Ga1−xAlxN nanowires with different Al constituents are calculated using first-principles plane-wave ultrasoft pseudopotential method. Results show that Ga1−xAlxN nanowires become more stable with increasing Al constituent. Bandgap of Ga1−xAlxN nanowires increases as the Al constituent increases but with a lower amplification compared with bulk Ga1−xAlxN. The peaks of static dielectric constants show a decreasing trend and move towards high-energy side as Al constituent increases. The absorption of Ga1−xAlxN nanowires shows an interesting phenomenon that it firstly increases and then decreases slightly as the Al constituent increases. Reflectivity of Ga1−xAlxN nanowires is much smaller than that of the bulk. The optical properties of Ga1−xAlxN nanowires show a blueshift effect as Al composition increases. According to these calculations, it is found that Ga1−xAlxN nanowires are appropriate to be applied into photoelectric detecting materials by adjusting the Al constituent of Ga1−xAlxN nanowires.