Phonon deformation potentials of hexagonal GaN studied by biaxial stress modulation

Lu, Junyong; Deng, Dongmei; Wang, Yong; Chen, Kevin J.; Lau, Kei May; Zhang, Tong‐Yi

doi:10.1063/1.3626532

Cited by 7 publications

(11 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The in-plane stress, i.e., the isotropic biaxial stress r biaxial , was calculated using the isotropic biaxial stress coefficient. [35][36][37] In this study, a value of À2.34 [cm À1 /GPa] was used, 36 which is the value for pure GaN and is close to the value of À2.43 proposed in Ref. 38.…”

Section: Resultsmentioning

confidence: 55%

Correlation between temperature dependence of Raman shifts and in-plane strains in an AlGaN/GaN stack

Kosemura

Sodan

Wolf

2017

Journal of Applied Physics

View full text Add to dashboard Cite

The temperature dependence of Raman shifts for different layers and different optical phonon modes in an AlGaN/GaN stack was examined in this study. The slopes of the Raman shifts as a function of temperature for the GaN and Al x GaN layers were found to vary, especially for the E 2 high mode compared with that for the A 1 (LO) mode. To further investigate these fluctuations in the temperature dependence of Raman shifts, a detailed evaluation was conducted for the depth distribution of in-plane strains in the AlGaN/GaN stack by detecting each of the layers simultaneously in a single Raman spectrum. The temperature dependence fluctuations for the E 2 high modes of the Al x GaN layers are considered to be related to the in-plane strain distribution with depth.

show abstract

Section: Resultsmentioning

confidence: 55%

Correlation between temperature dependence of Raman shifts and in-plane strains in an AlGaN/GaN stack

Kosemura

Sodan

Wolf

2017

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…For the as-grown sample, two Raman spectral peaks are observed at 567.1 and 732.1 cm −1 , which can be attributed to the E 2 (high) and A 1 (LO) phonon modes, respectively. 29,30 The initial etch to a depth of 225 nm barely shifts the Raman peaks, which are observed at 567.1 and 731.6 cm −1 respectively. These correspond to a relative in-plane strain of −0.125%.…”

Section: Resultsmentioning

confidence: 99%

“…The estimated in-plane strain relative to the as-grown sample, as calculated using the peak values of the E 2 (high) and A 1 (LO) from the Raman spectra, , are shown in Figure b. For the as-grown sample, two Raman spectral peaks are observed at 567.1 and 732.1 cm –1 , which can be attributed to the E 2 (high) and A 1 (LO) phonon modes, respectively. , The initial etch to a depth of 225 nm barely shifts the Raman peaks, which are observed at 567.1 and 731.6 cm –1 respectively. These correspond to a relative in-plane strain of −0.125%.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 7a shows the measured Raman spectra of the straininducing inverted nanoconical frustum array at different etch depths, together with the spectrum of the as-grown sample as a reference. The estimated in-plane strain relative to the asgrown sample, as calculated using the peak values of the E 2 (high) and A 1 (LO) from the Raman spectra, 29,30 are shown in Figure 7b. For the as-grown sample, two Raman spectral peaks are observed at 567.1 and 732.1 cm −1 , which can be attributed to the E 2 (high) and A 1 (LO) phonon modes, respectively.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Strain-Induced Spectral Red-Shifting from Nanoscale Frustum Arrays Fabricated over InGaN/GaN Quantum Wells for Light-Emitting Applications

Choi

2020

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

While spectral blue-shifting caused by nanostructuring of InGaN/GaN quantum wells has been widely reported for altering the emission color of light-emitting diodes, the same cannot be said for spectral red-shifting. It is well-known that nanostructuring of the quantum wells gives rise to relaxation of the strain incurred in the quantum wells, reducing the quantum confined stark effect with a consequence of spectral shifting to shorter wavelengths. In this report, we demonstrate a nanostructure configuration that produces the opposite effect, spectral red-shifting, by increasing the strain in the quantum wells through the formation of an inverted nanoconical-frustum array over the quantum wells, without allowing the nanostructures to penetrate through the quantum wells. Under such conditions, spectral red-shifting of the photoluminescence spectrum can be observed, consistent with the prediction of strain induction in the quantum wells by molecular dynamics simulations. Experimentally, spectral red-shift of the photoluminescence spectrum by up to 7.6 nm has been observed, when the proposed nanostructures are fabricated on InGaN/GaN quantum wells grown on a c-plane sapphire substrate with a nominal emission wavelength of ∼560 nm.

show abstract

“…, where, in case of the Raman peak w » E , H 2 0 568 rel. cm −1 is a still-debated stress-free value [12,15] and K=4.2 cm −1 GPa −1 is an experimentally measured phonon deformation potential [12,23]. The Raman scattering was excited by a 488nm wavelength laser with 10 mW power, focused through an intermediate magnification/numerical aperture×20/0.4 dry objective lens.…”

Section: Local Stress Analysis Via Confocal Raman Spectroscopymentioning

confidence: 99%

MOVPE growth of GaN on patterned 6-inch Si wafer

et al. 2020

View full text Add to dashboard Cite

We demonstrate that thicker layers can be achieved in gallium nitride (GaN) epitaxy by using a patterned silicon (Si) substrate compared to a planar Si substrate. GaN films were grown by metalorganic vapour-phase epitaxy on 6-inch Si (111) substrates patterned with arrays of squares with various corner shapes, height and lateral dimensions. Stress spatial distributions in the GaN pattern units were mapped out using confocal Raman spectroscopy. It was found that the corner shapes have an effect on the uniformity of the stress distribution. Patterns with round corners were found to have more uniform stress distribution than those with sharp corners. The largest crack-free square size for a 1.5 μm thick GaN film is 500×500 μm 2 .

show abstract

Phonon deformation potentials of hexagonal GaN studied by biaxial stress modulation

Cited by 7 publications

References 22 publications

Correlation between temperature dependence of Raman shifts and in-plane strains in an AlGaN/GaN stack

Correlation between temperature dependence of Raman shifts and in-plane strains in an AlGaN/GaN stack

Strain-Induced Spectral Red-Shifting from Nanoscale Frustum Arrays Fabricated over InGaN/GaN Quantum Wells for Light-Emitting Applications

MOVPE growth of GaN on patterned 6-inch Si wafer

Contact Info

Product

Resources

About