文摘
The strains of bond lengths and lattice in GaN/ultrathin InN/GaN quantum wells are modified by varying the well and barrier thickness. Inspection of position-dependent densities of state (DOS) calculated by ab initio simulations shows that this tunable strain significantly affects the electronic structures. The band gap and the band bending of the well decrease as the well width increases, whereas they are enhanced with an increase of the barrier thickness. The coherence and strain variation are realized by metalorganic chemical vapor deposition, according to the results of high resolution transmission electron microscopy and X-ray diffraction. Remarkable emission in the short wavelength region from the quantum wells is observed by cathodoluminescence to shift in the trend of the simulated band gap variation. The results show that the strained quantum wells have advantages for phase separation suppression and band structures engineering in the short wavelength region.