Structural dependence of electronic properties in (10(1)over-bar-0) wurtzite GaN/AlGaN quantum wells

Electronic properties of (10 (1) over bar0)-oriented wurtzite (WZ) GaN/AlGaN quantum well (QW) structures are investigated as a function of structural parameters such as Al composition and well width. These results are compared with those of (0001)-oriented WZ GaN/AlGaN QWs with the piezoelectric (PZ) and spontaneous (SP) polarization effects taken into account. In the case of a (0001)-oriented GaN/AlGaN QW, it is observed that the transition energy decreases with the well width and its rate of decrease increases with Al composition. On the other hand, the transition energies for a (10 (1) over bar0)-oriented GaN/AlGaN QW are a weak function of the well width and gradually decrease with increasing well width. The valence hand structure of the (0001)-oriented QW structure shows that the hole effective mass is nearly independent of the Al composition. In the case of the (10 (1) over bar0)-oriented structure. however, it is observed that the hole effective mass of the topmost valence band along k(y)' is significantly reduced with increasing Al composition, The optical matrix elements near the band edge (k(x)' = k(y)' = 0) of the (10 (1) over bar0)-oriented GaN/AlGaN QW are more than four times as large as those of the (0001)-oriented GaN/AlGaN QW in the investigated ranges of the Al composition and well width.