Improvement of crystal quality and optical property in (11−22) semipolar InGaN/GaN LEDs grown on patterned m-plane sapphire substrate

Topical Review: Development of overgrown semi-polar GaN for high efficiency green/yellow emission

“…To date, there have been few reports on the growth of long wavelength (green/yellow spectral region) emitters grown on [101], demonstrating an improved performance compared with semi-polar LEDs grown on planar sapphire. Okada et al [53] reported 506 nm green LEDs grown on patterned r-plane sapphire in 2012, where the stripe patterning process has been discussed above in section 3.2.…”

Improved Performance of (112̄2) Semipolar InGaN/GaN Light-Emitting Diodes Grown Using a Hemispherically Patterned SiO2 Mask

“…14,27) As shown in the TEM images, many defects were generated in (11 22) GaN grown on m-planar, in comparison with those of HPSS and HP-SiO 2 . Although more defects were reduced in the ( 1122) GaN layer on HPSS than that of m-planar, 20) as shown in Fig. 5(b), some defects were also generated in the interface between ( 1013) GaN nuclei [confirmed from XRD !=2 c-axis scan in Fig.…”

“…[15][16][17][18] Additionally, a hemispherically patterned sapphire substrate (HPSS) has been used to reduce defect density as well as to improve the light extraction efficiency of (11 20) nonpolar and (11 22) semipolar InGaN/GaN LEDs. 19,20) Actually, many defects were reduced in nonpolar and semipolar GaN layers grown on HPSS. However, in case of (11 22) semipolar structures, some defects were generated in the interface between GaN nuclei and hemispherical patterns.…”

“…However, in case of (11 22) semipolar structures, some defects were generated in the interface between GaN nuclei and hemispherical patterns. 20) This phenomenon limited the defect reduction effect of creating high-performance semipolar InGaN/GaN LEDs on HPSS. To overcome this problem, we introduced a hemispherically patterned silicon dioxide mask on m-plane sapphire (HP-SiO 2 ).…”

Characterization of a-plane InGaN light-emitting diodes with a SiNx interlayer grown on a patterned sapphire substrate by metal–organic chemical vapor deposition

“…However, nonpolar GaN grown on r-plane sapphire substrates usually contains numerous partial dislocations (PDs) and stacking faults (SFs) owing to the large lattice mismatch between the GaN and the sapphire substrate. To minimize these defects, various defect density reduction techniques such as lateral epitaxial overgrowth (LEO) 1) and pendeo epitaxy (PE) 2) and the use of a patterned sapphire substrate (PSS), [3][4][5][6] a SiO 2 nanorod, 7) and an SiN x interlayer 8,9) have been studied. However, LEO and PE are too complicated and time-consuming owing to a separate regrowth process.…”