STEM‐CL investigations on the influence of stacking faults on the optical emission of cubic GaN epilayers and cubic GaN/AlN multi‐quantum wells

Kemper, Ricarda M.; Veit, Peter; Mietze, C.; Dempewolf, Anja; Wecker, T.; Bertram, F.; Christen, J.; Lindner, J.K.N.; As, D. J.

doi:10.1002/pssc.201400154

Cited by 20 publications

(22 citation statements)

References 13 publications

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“…However, zb-GaN films with high phase purity are difficult to grow since the zincblende structure is metastable, and stacking faults and inclusions of the thermodynamically more stable wurtzite phase commonly occur [15][16][17] .…”

Section: Introductionmentioning

confidence: 99%

Effect of growth temperature and V/III-ratio on the surface morphology of MOVPE-grown cubic zincblende GaN

Lee

Frentrup

Kappers

et al. 2018

Journal of Applied Physics

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The influence of growth temperature and V/III-ratio on the surface morphology of (001) cubic zincblende GaN epilayers during metal organic vapour phase epitaxy (MOVPE) growth has been investigated using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The zincblende phase purity as determined by X-ray diffraction (XRD) was found to be above 98 % for most GaN epilayers studied. As the growth temperature was increased from 850 °C to 910 °C, and as the V/III-ratio was separately increased from 38 to 300, surface features were found to be elongated in [1-10] direction, and the ratio of the length to width of such surface features was found to increase. Faceting was observed at V/III-ratios below 38 and above 300, which in the latter case was accompanied by a reduction of the zincblende phase purity. An explanation for these morphological trends is proposed based on effects such as the reduced symmetry of the top monolayer of the (001)-2 oriented zincblende GaN lattice, diffusion of Ga and N adatoms on such a surface, and the relative energies of the crystal facets.

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Section: Introductionmentioning

confidence: 99%

Effect of growth temperature and V/III-ratio on the surface morphology of MOVPE-grown cubic zincblende GaN

Lee

Frentrup

Kappers

et al. 2018

Journal of Applied Physics

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“…These values directly reflect the density of structural defects. − Furthermore, they are extremely robust as they are reproducibly measured and commonly reported in most publications featuring epitaxial growth. However, it is important to consider the layer thickness d when comparing Δω of thin films as Δω decreases with increasing layer thickness. ,, This is depicted in Figure , by dark gray symbols representing the samples of this work. The thickest film shows the narrowest Δω.…”

Section: Resultsmentioning

confidence: 92%

AlN Buffer Enhances the Layer Quality of MBE-Grown Cubic GaN on 3C-SiC

Zscherp

Mengel

Hofmann

et al. 2022

Crystal Growth & Design

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Cubic nitrides are candidate materials for next-generation optoelectronic applications as they possess no internal fields and promise to cover large parts of the electromagnetic spectrum from the deep UV toward the mid-infrared. Their successful application demands high-quality epitaxial growth of c-GaN as a base material. This infers a virtually perfect crystallinity as well as smooth surfaces and interfaces despite the limited availability of suitable substrate materials. Here, we systematically introduce pre-growth treatments and c-AlN buffer layers to optimize c-GaN epitaxial layers. Optimized growth parameters yield extremely small surface roughness values below 1 nm root mean square of phase pure c-GaN layers with very limited stacking fault densities as highlighted by scanning transmission electron microscopy. The crystallinity is monitored by X-ray diffraction and surpasses the current standards. We study the effects of the pre-growth procedures on the optical response by photoluminescence spectroscopy and reconfirm the high structural quality of the epitaxial layers. The combined optimization of all layer properties through the universally applicable approach allows for the growth of more complex quantum structures toward device applications.

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“…Meaning both the phase purity and planar structural defects are unaffected by the annealing process. Thus the decrease in non-radiative recombination is unlikely to be caused by planar defects such as stacking faults, which have been suggested to act as centres of non-radiative recombination in zb-GaN 36 and are the dominant defect in zb-GaN epilayers 25 . However, these XRD profiles do not provide information on lower dimensional defects such as threading dislocations (1D) and point defects (0D).…”

Section: Thermally Annealed Mg-doped Zb-ganmentioning

confidence: 99%

The effect of thermal annealing on the optical properties of Mg-doped zincblende GaN epilayers

Dyer

Church

Jain³

et al. 2021

Journal of Applied Physics

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The effects of thermal annealing on the optical properties of Mg-doped cubic zinc-blende GaN epilayers grown by metalorganic chemical vapor deposition on 3C-SiC/Si (001) substrates are investigated. The photoluminescence spectra show near band edge features and a blue luminescence band that depend on Mg concentration, temperature and excitation power density. Annealing the sample in a N 2 atmosphere causes the intensity of the blue band to increase by a factor of 5. Power dependent photoluminescence measurements show a reduction in the laser excitation density required for saturation of the blue band after annealing, indicating an increase in the recombination lifetime. Time decay measurements confirm this increase, which is attributed to a reduction in the concentration of non-radiative defects after annealing. The results presented here are compared to those reported previously for Mg-doped hexagonal wurtzite GaN.

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STEM‐CL investigations on the influence of stacking faults on the optical emission of cubic GaN epilayers and cubic GaN/AlN multi‐quantum wells

Cited by 20 publications

References 13 publications

Effect of growth temperature and V/III-ratio on the surface morphology of MOVPE-grown cubic zincblende GaN

Effect of growth temperature and V/III-ratio on the surface morphology of MOVPE-grown cubic zincblende GaN

AlN Buffer Enhances the Layer Quality of MBE-Grown Cubic GaN on 3C-SiC

The effect of thermal annealing on the optical properties of Mg-doped zincblende GaN epilayers

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