Investigation of carrier transport properties in semipolar (112¯2) GaN films with low defect density

Jang, Soohwan; Kim, Hyonwoong; Kim, Doo Soo; Hwang, Soon Jung; Kim, Ji Hyun; Baik, Kwang Hyeon

doi:10.1063/1.4825171

Cited by 13 publications

(13 citation statements)

References 41 publications

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“…The dark lines running across the image are BSFs. From the TEM observation, the density of BSFs was 9.6 × 10 5 cm −1 , similar to many previous reports 23 33 .…”

Section: Resultssupporting

confidence: 90%

“…An M-shaped azimuthal dependence of FWHM values over 360° angle range was observed in Fig. 2(d) , which is similar to the observation reported for MOCVD a-GaN 29 and (11–22) GaN 22 30 31 32 33 . The broadening of (11–22) XRC FWHM along the [1–100] direction is caused by the larger distortion of the GaN lattice due to higher density of defects such as threading dislocations, stacking faults (SFs), as well as a larger mosaic tilt and/or a reduced coherent length (smaller size of the mosaic blocks) 32 34 .…”

Section: Resultssupporting

confidence: 86%

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Anisotropic structural and optical properties of semi-polar (11–22) GaN grown on m-plane sapphire using double AlN buffer layers

Zhao

Wang

Yang

et al. 2016

Sci Rep

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We report the anisotropic structural and optical properties of semi-polar (11–22) GaN grown on m-plane sapphire using a three-step growth method which consisted of a low temperature AlN buffer layer, followed by a high temperature AlN buffer layer and GaN growth. By introducing double AlN buffer layers, we substantially improve the crystal and optical qualities of semi-polar (11–22) GaN, and significantly reduce the density of stacking faults and dislocations. The high resolution x-ray diffraction measurement revealed that the in-plane anisotropic structural characteristics of GaN layer are azimuthal dependent. Transmission electron microscopy analysis showed that the majority of dislocations in the GaN epitaxial layer grown on m-sapphire are the mixed-type and the orientation of GaN layer was rotated 58.4° against the substrate. The room temperature photoluminescence (PL) spectra showed the PL intensity and wavelength have polarization dependence along parallel and perpendicular to the [1–100] axis (polarization degrees ~ 0.63). The realization of a high polarization semi-polar GaN would be useful to achieve III-nitride based lighting emission device for displays and backlighting.

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“…The dark lines running across the image are BSFs. From the TEM observation, the density of BSFs was 9.6 × 10 5 cm −1 , similar to many previous reports 23 33 .…”

Section: Resultssupporting

confidence: 90%

Section: Resultssupporting

confidence: 86%

Anisotropic structural and optical properties of semi-polar (11–22) GaN grown on m-plane sapphire using double AlN buffer layers

Zhao

Wang

Yang

et al. 2016

Sci Rep

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“…So far, there are only a few reports investigating the electrical properties of semi-polar GaN [94][95][96], possibly due to two major reasons; firstly, the crystal quality of available semi-polar GaN is not good enough, and secondly, due to the anisotropic nature of semi-polar GaN, it would not be easy to measure its electrical properties.…”

Section: Electrical Characteristicsmentioning

confidence: 99%

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

Wang

2016

Semicond. Sci. Technol.

109

118

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The most successful example of large lattice-mismatched epitaxial growth of semiconductors is the growth of III-nitrides on sapphire, leading to the award of the Nobel Prize in 2014 and great success in developing InGaN-based blue emitters. However, the majority of achievements in the field of III-nitride optoelectronics are mainly limited to polar GaN grown on c-plane (0001) sapphire. This polar orientation poses a number of fundamental issues, such as reduced quantum efficiency, efficiency droop, green and yellow gap in wavelength coverage, etc. To date, it is still a great challenge to develop longer wavelength devices such as green and yellow emitters. One clear way forward would be to grow III-nitride device structures along a semi-/non-polar direction, in particular, a semi-polar orientation, which potentially leads to both enhanced indium incorporation into GaN and reduced quantum confined Stark effects. This review presents recent progress on developing semi-polar GaN overgrowth technologies on sapphire or Si substrates, the two kinds of major substrates which are cost-effective and thus industry-compatible, and also demonstrates the latest achievements on electrically injected InGaN emitters with long emission wavelengths up to and including amber on overgrown semi-polar GaN. Finally, this review presents a summary and outlook on further developments for semi-polar GaN based optoelectronics.

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“…[2]. The other approach is AlN nucleation, which 3 . Nucleation is then stopped and the temperature is ramped to 1140-1200…”

Section: Methodsmentioning

confidence: 99%

“…The (1122) orientation can be obtained by GaN epitaxy on m-plane (1010) sapphire substrates. But such templates have typically a huge density of dislocations in the 10 10 cm −2 range and basal-plane stacking faults (BSFs) in the upper 10 5 cm −1 range [1][2][3]. Furthermore, contributions from the unwanted (1013) phase have been observed [4,5].…”

mentioning

confidence: 99%

Optimizing GaN () hetero‐epitaxial templates grown on () sapphire

Pristovsek

Frentrup

Han

et al. 2015

Physica Status Solidi (b)

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The hetero‐epitaxy of (11true2‾2) GaN on (10true1‾0) sapphire was optimized in metal–organic vapor phase epitaxy. Best results were obtained from an AlN nucleation followed by AlN and AlGaN layers, and inserting low‐temperature AlN interlayers (ILs) as well as a SiNx IL. X‐ray diffraction (XRD) of ω scans of the symmetric (11true2‾2) reflection yielded an ω FWHM <450″ along [11true2‾true3‾] and <900″ along [10true1‾0] together with a 100×100thinmathspaceμm2 rms roughness below 10 nm as determined by atomic force microscopy. The lowest threading dislocation density achieved was ≈109cm−2 while the basal plane stacking fault density was in the lower 105cm−1 range as determined by transmission electron microscopy. The suppression of the unwanted (10true1‾true3‾) phase was lower than 1 in 10,000 as judged from XRD.

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Investigation of carrier transport properties in semipolar (112¯2) GaN films with low defect density

Cited by 13 publications

References 41 publications

Anisotropic structural and optical properties of semi-polar (11–22) GaN grown on m-plane sapphire using double AlN buffer layers

Anisotropic structural and optical properties of semi-polar (11–22) GaN grown on m-plane sapphire using double AlN buffer layers

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

Optimizing GaN () hetero‐epitaxial templates grown on () sapphire

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