Improvements in a-plane GaN crystal quality by AlN/AlGaN superlattices layers

Polar dependence of impurity incorporation and yellow luminescence in GaN films grown by metal-organic chemical vapor deposition

“…The problem can be avoided by growing GaN in nonpolar orientations, in which the polar c-axis is at 901 to the growth direction; alternatively, the electric field can also be reduced by growing in semipolar orientations, in which the c-axis is at an acute angle to the growth plane [2]. So recently there have been considerable interests in the growth of nonpolar and semipolar gallium nitride based on epitaxial films, heterostructures and devices [3][4][5][6][7][8]. The polar properties of GaN make the behaviors of the different polar directions distinct, especially when there is impurity incorporated.…”

Defect reduction in (112̄0) nonpolar a-plane GaN grown on r-plane sapphire using TiN interlayers

“…The growth on foreign substrates typically leads to the presence of built-in strain in heteroepitaxial nitride layers due to the difference in lattice parameters and thermal expansion coefficients between layers and substrates. Furthermore, the growth rate along the c-direction was much higher than that along the m-direction, so the pleat morphology comes forth and produced the strain [3]. Generally, the anisotropy reflected in the XRD is the omega X-ray rocking curves (RCs) of the (1 1 2 0) plane changed with the degree of the phi and show a shape of ''w'' [3].…”

“…Recently, there have been considerable interests in the growth of gallium nitride along the nonpolar direction, which can reduce the quantum-confined Stark effect, in turn the carrier recombination rate in an InGaN/GaN quantum well [1][2][3][4][5]. Due to its relatively low cost, the r-plane sapphire substrate has been widely used substrate for the nonpolar a-plane GaN growth so far.…”

Effect of defects on strain state in nonpolar a-plane GaN

“…After that, a GaN regrown layer with thickness of 6 mm was deposited, and this sample was denoted as sample D. Detailed growth condition can be found in Refs. [18,19].…”