MOCVD growth of vertically aligned InGaN nanowires

Vertically aligned InGaN nanowires with engineered axial In composition for highly efficient visible light emission

“…A similar triangular cross-section was observed in GaN NWs grown by the same technique, which may be attributed to the competitive nature of the growth kinetics on different facets 21 22 . The three faces of the isosceles triangular cross-section of the InGaN NWs can be indexed as the c-plane for the base and two inclined facets, which is consistent with the recent reports of InGaN NWs grown by MOCVD 15 . The high density and the orientation of the InGaN NWs on the substrate are shown in Fig.…”

“…As shown in Fig. 1(a) , InGaN NWs were mostly grown vertically on the r-plane sapphire surface, suggesting that their growth direction was , which is the direction normal to the r-plane face of the sapphire substrate 15 20 . A magnified cross-sectional image of an ensemble of InGaN NWs is shown in Fig.…”

“…A phase separation in MBE-grown InGaN NWs was also revealed using hard X-ray synchrotron nanoprobe techniques 17 . Recently, it was also reported that MOCVD-grown InGaN NWs are characterized by a multi-peak broad emission resulting from the In-concentration fluctuations 15 . Both In fluctuations and phase separation in InGaN NWs can lead to anisotropic carrier recombination, producing broad spectra with two (or more) emission peaks, typically at the low and high energy sides of the visible spectrum 15 17 18 .…”

“…Recently, there have been several reports on the synthesis of InGaN NWs by hydride vapour-phase epitaxy (HVPE) 10 and RF-molecular beam epitaxy (RF-MBE) 13 14 ; however, the growth of InGaN NWs using metalorganic chemical vapour deposition (MOCVD) has rarely been reported 15 . The growth of InGaN NWs by HVPE is limited by the hydrogen-induced In etching, which can significantly reduce the In content and form unreactive In species 10 .…”

“…Furthermore, extrinsic doping and fabrication of heterojunctions are not available via the HVPE and RF-MBE techniques. In contrast, MOCVD is known for its scalability in the growth of high quality and single crystalline III–V NWs with In contents sufficiently high for light emission in the yellow-green-red spectral ranges 15 . In addition, heteroepitaxy and p-n junction doping are easily achieved using the MOCVD platform, which makes it a promising technique for device applications.…”