Probing carrier concentration of doped GaN single crystals from LO phonon-plasmon coupled modes

Li, Linxuan; Zhu, Siqi; Cheng, Lap‐Tak; Qi, Hongsheng; Fan, Yu; Zheng, Wei

doi:10.1016/j.jlumin.2022.119214

Cited by 4 publications

(3 citation statements)

References 36 publications

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“…From Equation (12), the carrier concentration can be expressed as:

where M =

0.2m 0 /4πe 2 = 1.1956 × 10 13 cm −1 , with

= 5.35, m*/m 0 = 0.2, [ 39 ], and with the free electron m 0 = 9.1 × 10 28 g and e = 1.602 × 10 −19 coulombs. Referring to the data of L. Li et al [ 40 ], i.e., an undoped GaN with ω p = 102 cm −1 and n = 1.18 × 10 17 cm −3 , we obtained M = n/

= 1.18 × 10 17 /(102) 2 = 1.134 × 10 13 (cm −1 ), which matches well with above calculation. We can calculate the carrier concentration n values for four GaN/Si samples, listed in Table 4 , which are in the range of 0.5–16 × 10 16 cm −3 .…”

Section: Resultssupporting

confidence: 90%

“…Raman scattering can offer a non-destructive experimental technique for the determination of the carrier concentration due to doping in semiconductors through the LO phonon and plasma coupling (LOPC). For wide bandgap semiconductors such as SiC, GaN, etc., the Raman LOPC spectral intensity has the following form [ 36 , 39 , 40 ],

where ε is the dielectric function, α is the polarizability, E is the macroscopic electric field, n ω is the Bose–Einstein factor, and n 1 and n 2 are refractive indices at incidence frequency ω 1 and scattering frequency ω 2 , respectively. In Equation (8),

where

is the longitudinal optical (LO) mode frequency,

is the transverse optical (TO) mode frequency, η is the phonon damping constant,

is the plasma damping constant, and C is the Faust–Henry coefficient with a value of ~0.35.…”

Section: Resultsmentioning

confidence: 99%

Section: Raman Spectral Analyses By Spatial Correlation Model Of Five...mentioning

confidence: 99%

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Optical, Structural, and Synchrotron X-ray Absorption Studies for GaN Thin Films Grown on Si by Molecular Beam Epitaxy

Feng,

Liu,

Xie

et al. 2024

Materials

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GaN on Si plays an important role in the integration and promotion of GaN-based wide-gap materials with Si-based integrated circuits (IC) technology. A series of GaN film materials were grown on Si (111) substrate using a unique plasma assistant molecular beam epitaxy (PA-MBE) technology and investigated using multiple characterization techniques of Nomarski microscopy (NM), high-resolution X-ray diffraction (HR-XRD), variable angular spectroscopic ellipsometry (VASE), Raman scattering, photoluminescence (PL), and synchrotron radiation (SR) near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. NM confirmed crack-free wurtzite (w-) GaN thin films in a large range of 180–1500 nm. XRD identified the w- single crystalline structure for these GaN films with the orientation along the c-axis in the normal growth direction. An optimized 700 °C growth temperature, plus other corresponding parameters, was obtained for the PA-MBE growth of GaN on Si, exhibiting strong PL emission, narrow/strong Raman phonon modes, XRD w-GaN peaks, and high crystalline perfection. VASE studies identified this set of MBE-grown GaN/Si as having very low Urbach energy of about 18 meV. UV (325 nm)-excited Raman spectra of GaN/Si samples exhibited the GaN E2(low) and E2(high) phonon modes clearly without Raman features from the Si substrate, overcoming the difficulties from visible (532 nm) Raman measurements with strong Si Raman features overwhelming the GaN signals. The combined UV excitation Raman–PL spectra revealed multiple LO phonons spread over the GaN fundamental band edge emission PL band due to the outgoing resonance effect. Calculation of the UV Raman spectra determined the carrier concentrations with excellent values. Angular-dependent NEXAFS on Ga K-edge revealed the significant anisotropy of the conduction band of w-GaN and identified the NEXAFS resonances corresponding to different final states in the hexagonal GaN films on Si. Comparative GaN material properties are investigated in depth.

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“…From Equation (12), the carrier concentration can be expressed as:

where M =

0.2m 0 /4πe 2 = 1.1956 × 10 13 cm −1 , with

Section: Resultssupporting

confidence: 90%

where

is the longitudinal optical (LO) mode frequency,

is the transverse optical (TO) mode frequency, η is the phonon damping constant,

is the plasma damping constant, and C is the Faust–Henry coefficient with a value of ~0.35.…”

Section: Resultsmentioning

confidence: 99%

Section: Raman Spectral Analyses By Spatial Correlation Model Of Five...mentioning

confidence: 99%

See 1 more Smart Citation

Optical, Structural, and Synchrotron X-ray Absorption Studies for GaN Thin Films Grown on Si by Molecular Beam Epitaxy

Feng,

Liu,

Xie

et al. 2024

Materials

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Ge-doping in polycrystalline GaN layer through electron beam evaporator deposition with successive ammonia annealing

Yusop,

Waheeda,

Alias

et al. 2024

Appl. Phys. A

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Carrier scattering and temperature characteristics of mobility and resistivity of Fe-doped GaN

Tian,

Pan,

Zhang

et al. 2024

J. Phys. D: Appl. Phys.

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The electron mobility and dark resistivity of Fe-doped semi-insulating GaN (GaN:Fe) are calculated over the temperature range from 10 K to 500 K by considering the impurities compensation mechanism and majority carrier scattering. The temperature characteristic curve of the mobility exhibits unimodality and the curve of resistivity decreases monotonically with rising temperature. The carrier scatterings induced by ionized impurities, acoustic deformation potential, piezoelectric, and polar optical phonons are analyzed. It is found that the mobility is determined by ionized impurity scattering, piezoelectric scattering, and polar optical phonon scattering in different temperature ranges, and the contribution of acoustic deformation potential scattering is negligible over the entire temperature range. Furthermore, the effects of concentrations of shallow donors and deep acceptors on the temperature characteristic curves of mobility and resistivity, the peak mobility and its corresponding temperature (peak temperature), and the mobility and resistivity at room temperature are discussed. Our simulation shows the calculation results agree very well with the reported experimental and theoretical results when the Fe-related level is selected as 0.58 eV below the conduction band edge. Understanding of thermal properties of dark resistivity and mobility can be useful for optimizing GaN:Fe-based electronic and photonic devices performance in different temperature regimes.

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Probing carrier concentration of doped GaN single crystals from LO phonon-plasmon coupled modes

Cited by 4 publications

References 36 publications

Optical, Structural, and Synchrotron X-ray Absorption Studies for GaN Thin Films Grown on Si by Molecular Beam Epitaxy

Optical, Structural, and Synchrotron X-ray Absorption Studies for GaN Thin Films Grown on Si by Molecular Beam Epitaxy

Ge-doping in polycrystalline GaN layer through electron beam evaporator deposition with successive ammonia annealing

Carrier scattering and temperature characteristics of mobility and resistivity of Fe-doped GaN

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