Efficient radiative recombination from ⟨112¯2⟩ -oriented InxGa1−xN multiple quantum wells fabricated by the regrowth technique

${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{N}$ multiple quantum wells (QWs) with $\left[0001\right]$ , $⟨11\overline{2}2⟩$ , and $⟨11\overline{2}0⟩$ orientations have been fabricated by means of the regrowth technique on patterned $\mathrm{GaN}$ template with striped geometry, normal planes of which are $\left(0001\right)$ and $\left\{11\overline{2}0\right\}$ , on sapphire substrates. It was found that photoluminescence intensity of the $\left\{11\overline{2}2\right\}$ QW is the strongest among the three QWs, and the internal quantum efficiency of the $\left\{11\overline{2}2\right\}$ QW was estimated to be as large as about 40% at room temperature. The radiative recombination lifetime of the $\left\{11\overline{2}2\right\}$ QW was about $0.38\mathrm{ns}$ at low temperature, which was 3.8 times shorter than that of conventional $\left[0001\right]$ -oriented ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{N}$ QWs emitting at a similar wavelength of about $400\mathrm{nm}$ . These findings strongly suggest the achievement of stronger oscillator strength owing to the suppression of piezoelectric fields.