Effect of Spontaneous Polarization Charges on the Electron Mobility  in ZnO Surface Quantum Wells

We present a theoretical study of the effect due to spontaneous polarization of ZnO on the low-temperature mobility of the two-dimensional electron gas (2DEG) in a ZnO surface quantum well (SFQW). We proved that for the O-polar face this causes an attraction of electrons by the positive charges bound on the surface, while for the Zn-polar face a repulsion of them far away therefrom by the negative bound charges of the same magnitude. Accordingly, surface roughness scattering is drastically enhanced in the former case, but reduced in the latter one. Therefore, the low-% temperature 2DEG mobility in ZnO SFQWs with O-polar face is found to be dominated by surface roughness. Our theory was illustrated for the sample prepared by bombardment of the O-polar face by 100-eV hydrogen ions. The surface roughness scattering enables an explanation of the 2DEG mobility, especially, the reason of low values for the mobility in the dependence from the carrier density which has not been understood when starting from impurity scattering.

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Low-temperature galvanomagnetic transport of the two-dimensional electron gas in GaAs quantum wells

Physical Review B ◽

10.1103/physrevb.48.17177 ◽

1993 ◽

Vol 48 (23) ◽

pp. 17177-17180 ◽

Cited By ~ 2

Author(s):

P. K. Ghosh ◽

D. Chattopadhyay

Keyword(s):

Low Temperature ◽

Quantum Wells ◽

Electron Gas ◽

Two Dimensional ◽

Dimensional Electron ◽

Two Dimensional Electron Gas ◽

Dimensional Electron Gas

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Transport Properties of Two-Dimensional Electron Gas in Cubic AlGaN/GaN Heterostructures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.873.777 ◽

2013 ◽

Vol 873 ◽

pp. 777-782

Author(s):

Qian Feng ◽

Peng Shi ◽

Jie Zhao ◽

Kai Du ◽

Yu Kun Li ◽

...

Keyword(s):

Theoretical Study ◽

Electron Gas ◽

Impurity Scattering ◽

Interface Roughness ◽

Dimensional Electron ◽

Barrier Thickness ◽

Al Content ◽

Alloy Disorder ◽

Dimensional Electron Gas ◽

Disorder Scattering

We presented a theoretical study of the dependence of 2DEG mobility on temperature, barrier thickness, Al content, donor concentration to reveal the internal physics of 2DEG mobility in cubic AlGaN/GaNheterostructures. The 2DEG mobility is modeled as a combined effect of the scattering mechanisms including acoustic phonons, ionized impurity, dislocation, alloy disorder and interface roughness scattering.The variation of mobility results mainly from the change of 2DEG density and temperature. It reveals the dominant scattering mechanismsare dislocation and alloy disorder scattering atlow temperature.Acoustic phonons scattering becomes the major limit at 300k. Impurity scattering plays the key role when donor density rises. We find a maximum mobility with a structure of 25% Al content and 4-5nm barrier thickness.

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Intrinsic Mobility Limits of a Two-Dimensional Electron Gas in AlGaN/GaN Heterostructures

MRS Proceedings ◽

10.1557/proc-449-573 ◽

1996 ◽

Vol 449 ◽

Cited By ~ 1

Author(s):

W. Walukiewicz ◽

L. Hsu ◽

J. M. Redwing

Keyword(s):

Low Temperature ◽

Theoretical Study ◽

Electron Gas ◽

Two Dimensional ◽

Optical Phonons ◽

Dimensional Electron ◽

Two Dimensional Electron Gas ◽

High Quality ◽

Structure Comparison ◽

Dimensional Electron Gas

ABSTRACTWe present the results of a theoretical study of the 2D electron gas mobility at a AlxGa1−xN/GaN heterointerface. All standard mechanisms, including scattering by acoustic and optical phonons, and remote and background (residual) impurities have been included in our calculation of theoretical mobility limits in a AlxGa1−xN/GaN structure. Comparison of calculations with experimental mobilities obtained from high quality MOCVD grown Al0.15Ga0.85N/GaN heterostructures shows that the low temperature mobility in these samples is dominated by scattering from ionized impurities, with a smaller contribution from acoustic phonons.

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Electron Mobility in an Unintentionally Doped GaN/AlGaN Surface Quantum Well

Communications in Physics ◽

10.15625/0868-3166/21/4/432 ◽

2012 ◽

Vol 21 (4) ◽

pp. 309

Author(s):

Nguyen Viet Minh

Keyword(s):

Quantum Well ◽

Quantum Wells ◽

Electron Mobility ◽

Theoretical Study ◽

Electron Gas ◽

Dimensional Electron ◽

Total Electron ◽

Hartree Potential ◽

Self Consistent ◽

Dimensional Electron Gas

We present a theoretical study the two-dimensional electron gas 2DEG at low temperature in an unintentionally doped GaN/AlGaN surface quantum well, taking adequate account of the roughness-induced scattering mechansms and effect due to sheet polarization charges. Within model of surface quantum wells 2DEG be described by an extended Fang-Howard wave function, we are able to derive an analytic expression for the self-consistent Hartree potential. Thus, we obtained simple expresion describing the enhancement of the 2DEG screening and unscreened\break potentials for different scattering sources. We studied the electron mobility due to different scattering sources and the total electron mobility in an unintentionally doped GaN/AlGaN surface quantum well.

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