Efficient radiative recombination from ⟨11(2)over-bar-2⟩-oriented InxGa1-xN multiple quantum wells fabricated by the regrowth technique

InxGa1-xN multiple quantum wells (QWs) with [0001], <11 (2) over bar2>, and <11 (2) over bar0> orientations have been fabricated by means of the regrowth technique on patterned GaN template with striped geometry, normal planes of which are (0001) and {11 (2) over bar0}, on sapphire substrates. It was found that photoluminescence intensity of the {11 (2) over bar2} QW is the strongest among the three QWs, and the internal quantum efficiency of the {11 (2) over bar2} QW was estimated to be as large as about 40% at room temperature. The radiative recombination lifetime of the {11 (2) over bar2} QW was about 0.38 ns at low temperature, which was 3.8 times shorter than that of conventional [0001]-oriented InxGa1-xN QWs emitting at a similar wavelength of about 400 nm. These findings strongly suggest the achievement of stronger oscillator strength owing to the suppression of piezoelectric fields. (C) 2004 American Institute of Physics.