Effects of initial stages on the crystal quality of nonpolar a-plane AlN on r-plane sapphire by low-pressure HVPE

Wu, Jerry J.; Katagiri, Yusuke; Okuura, Kazuki; Li, Dabing; Miyake, Hideto; Hiramatsu, Kazumasa

doi:10.1016/j.jcrysgro.2009.06.014

Cited by 23 publications

(14 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, u is the angle of rotation about the surface normal and v is the angle of sample tilted about the axis formed by the intersection of the Bragg and scattering planes. After tilting the sample to the suitable v for specific off axis reflections, U scan were performed to find the GaN (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and sapphire (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) reflections for sample A and GaN (0002) and sapphire (20)(21)(22)(23)(24) reflections for sample B. Due to symmetry of hexagonal structure, when a tilt of v ¼ 60 is made, both GaN (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and sapphire (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) peaks showed a two fold symmetry.…”

Section: Resultsmentioning

confidence: 99%

“…When nitridation treatment was given to the substrate, the epilayers exhibited a distinct structural difference compared to the corresponding ones with no nitridation treatment. [21][22][23][24] Kehagias et al 25 26 AlN layer hence formed promotes the growth of GaN epilayer in the (10-10) orientation. The optical properties of GaN films were characterized by room temperature PL measurement using a He-Cd laser (k ¼ 325 nm) as the excitation source and is shown Fig.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Semipolar and nonpolar GaN epi-films grown on m-sapphire by plasma assisted molecular beam epitaxy

Mukundan

Mohan

Chandan

et al. 2014

Journal of Applied Physics

View full text Add to dashboard Cite

We hereby report the development of non-polar epi-GaN films of usable quality, on an m-plane sapphire. Generally, it is difficult to obtain high-quality nonpolar material due to the planar anisotropic nature of the growth mode. However, we could achieve good quality epi-GaN films by involving controlled steps of nitridation. GaN epilayers were grown on m-plane (10-10) sapphire substrates using plasma assisted molecular beam epitaxy. The films grown on the nitridated surface resulted in a nonpolar (10-10) orientation while without nitridation caused a semipolar (11-22) orientation. Room temperature photoluminescence study showed that nonpolar GaN films have higher value of compressive strain as compared to semipolar GaN films, which was further confirmed by room temperature Raman spectroscopy. The room temperature UV photodetection of both films was investigated by measuring the I-V characteristics under UV light illumination. UV photodetectors fabricated on nonpolar GaN showed better characteristics, including higher external quantum efficiency, compared to photodetectors fabricated on semipolar GaN. X-ray rocking curves confirmed better crystallinity of semipolar as compared to nonpolar GaN which resulted in faster transit response of the device.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Semipolar and nonpolar GaN epi-films grown on m-sapphire by plasma assisted molecular beam epitaxy

Mukundan

Mohan

Chandan

et al. 2014

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The internal fields can be strongly reduced by changing the epitaxial growth direction from the conventional polar c - direction into less polar crystal directions 5 . Based on this idea, researchers have made great efforts to fabricate semi-polar AlN on r -sapphire, r -LiAlO2, a -ZnO, a - and m-plane SiC 6 7 8 9 10 . However, the epitaxy on such non- c-plane wafers is much more challenging than that on conventional polar c-plane sapphire or SiC 11 .…”

mentioning

confidence: 99%

Nucleation and growth of (10͞11) semi-polar AlN on (0001) AlN by Hydride Vapor Phase Epitaxy

Liu

Zhang

et al. 2016

Sci Rep

View full text Add to dashboard Cite

Wurtzite AlN is widely used for deep ultraviolet optoelectronic devices (DUV), which are generally grown along the [0001]-direction of the wurtzite structure on currently available substrates. However, huge internal electrostatic fields are presented within the material along [0001] axis induced by piezoelectric and spontaneous polarization, which has limited the internal quantum efficiency of AlN based DUV LEDs dramatically. The internal fields can be strongly reduced by changing the epitaxial growth direction from the conventional polar c-direction into less polar crystal directions. Twinned crystal is a crystal consisting of two or more domains with the same crystal lattice and composition but different crystal orientations. In other words, twins can be induced to change crystal directions. In this work we demonstrated that the epitaxial growth of () semi-polar AlN on (0001) AlN by constructing () and () twin structures. This new method is relative feasible than conventional methods and it has huge prospect to develop high-quality semi-polar AlN.

show abstract

“…However, there has been no report about the growth of thick nonpolar AlN (1 1 2 0) and (1 1 0 0) layers by HVPE. Recently, we have reported on the low-pressure LP-HVPE growth of thick AlN (1 1 2 0) layers on sapphire (1 1 0 2) substrates using a high growth temperature and a two-step buffer method [12,13].…”

Section: Introductionmentioning

confidence: 99%

In-plane structural anisotropy and polarized Raman-active mode studies of nonpolar AlN grown on 6H-SiC by low-pressure hydride vapor phase epitaxy

Okuura

Okumura

et al. 2010

Journal of Crystal Growth

Self Cite

View full text Add to dashboard Cite

Effects of initial stages on the crystal quality of nonpolar a-plane AlN on r-plane sapphire by low-pressure HVPE

Cited by 23 publications

References 29 publications

Semipolar and nonpolar GaN epi-films grown on m-sapphire by plasma assisted molecular beam epitaxy

Semipolar and nonpolar GaN epi-films grown on m-sapphire by plasma assisted molecular beam epitaxy

Nucleation and growth of (10͞11) semi-polar AlN on (0001) AlN by Hydride Vapor Phase Epitaxy

In-plane structural anisotropy and polarized Raman-active mode studies of nonpolar AlN grown on 6H-SiC by low-pressure hydride vapor phase epitaxy

Contact Info

Product

Resources

About