Semipolar (11 22) GaN was achieved by controlling anisotropic growth rates in a maskless r -plane patterned sapphire substrate. Upon optimizing the growth conditions, the growth rate of the GaN layer on etched c-plane-like sapphire was much higher than that on other planes such as the original r -plane sapphire. Singularly ( 1122)-oriented GaN was confirmed when GaN was grown on only the c-plane-like sapphire sidewall. The control of the anisotropic growth rate is useful for growing nonpolar and semipolar layers using maskless patterned substrates.

GaN‐based light‐emitting diodes (LEDs) were fabricated on nanopatterned sapphire substrates (nano‐PSSs) by thermal lithography with laser irradiation. The characteristics of the LEDs were measured by X‐ray diffraction analysis and scanning electron microscopy. The crystalline qualities of the LEDs deteriorated with the shortening of the nanopattern periods. The nucleation of GaN was initiated from the nanopatterns, which increased the number of grain boundaries. The output power of the LEDs on the nano‐PSSs with a diameter of 200 nm and 500 nm periods was 70% higher than that on flat sapphire substrate. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

We succeeded in growing a semipolar (11$ \bar 2 $2) GaN layer on a patterned r ‐plane sapphire substrate (r ‐PSS) without a SiO2 mask by metal‐organic vapor phase epitaxy. Under various growth conditions, the semipolar (11$ \bar 2 $2) GaN layer was only grown on the c ‐plane‐like sapphire sidewall of the r ‐PSS without a SiO2 mask which shows r ‐PSS is useful to obtain (11$ \bar 2 $2) GaN. The specific characteristics of the (11$ \bar 2 $2) GaN on the r ‐PSS were investigated by X‐ray diffraction measurement, atomic force microscopy (AFM), transmission electron microscopy and photoluminescence. The full width at half maximum of X‐ray rocking curve of coalesced sample were 722 and 319 arcsec along the azimuths parallel and perpendicular to the c ‐direction, respectively. The macrosteps were observed by AFM observation. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

We succeeded in the fabrication of a thick InGaN template by (11$ \bar 2 $2) facet growth and mass transport. Thick InGaN was grown on a GaN (11$ \bar 2 $2) facet with a stable facet structure. After 20 min annealing under a flow of NH3 and N2, the InGaN with the (11$ \bar 2 $2) facet was perfectly embedded owing to mass transport. Subsequently, a multiple‐quantum‐well structure was fabricated on the InGaN template and characterized using monochromatic cathodeoluminescence measurement. As a result, we found that there were two regions with peak emission wavelengths of 420 and 500 nm because of the compositional pulling effect. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

We grew nonpolar m ‐plane GaN by selective area growth and epitaxial lateral overgrowth. In this report, we investigated the growth mechanism of m ‐plane GaN on a patterned a ‐plane sapphire substrate (a ‐PSS) without an SiO2 mask. With the control of the anisotropic growth rate of c ‐plane GaN on an original a ‐plane sapphire surface and on a c ‐plane‐like sapphire sidewall in the a ‐PSS, c ‐plane GaN was grown only on the c ‐plane‐like sapphire sidewall, resulting in a pure‐oriented m ‐plane GaN layer on the a ‐PSS. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)