Effect of annealing atmosphere on the quality of ZnO crystal surface

Grasza, K.; Łusakowska, E.; Skupiński, P.; Kopalko, K.; Bąk‐Misiuk, J.; Mycielski, A.

doi:10.1002/pssb.200675110

Cited by 11 publications

(6 citation statements)

References 10 publications

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“…This is related to the poor quality of the ZnO surface as mentioned before. [21][22][23] In addition, the roughness amplitude of the H 2 + -ion implanted sample is larger as hydrogen doping may bring about an increase of surface roughness. 66,67 From Figs.…”

Section: Numerical Results and Comparison With Experimentsmentioning

confidence: 99%

“…17,20 Recent experimental studies provided evidence that the pure ZnO layer is rather rough. [21][22][23] Further, it was pointed out [24][25][26] that ZnO in the natural ͑wurtzite͒ phase has a large spontaneous polarization ͑twice of that of GaN͒. This must exert some influence on electron transport in ZnO-based structures, however, scarcely studied.…”

Section: Introductionmentioning

confidence: 99%

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Electron mobility in Gaussian heavily doped ZnO surface quantum wells

2008

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We present a theory of the low-temperature mobility of electrons in a Gaussian heavily doped zinc oxide surface quantum well ͑ZnO SFQW͒, taking into account both surface impurity and surface roughness scattering. The theory also includes strong confinement due to spontaneous polarization charges on the surface of ZnO. The electron distribution is found to be shifted closer to the surface for the O-polar face, while far away therefrom for the Zn-polar one. Accordingly, both scatterings are remarkably enhanced in the former case, while reduced in the latter one. Further, high-temperature Coulomb correlation among the charged impurities at a high density in a sample subjected to thermal treatment is proven to significantly reduce scattering by them. Therefore, in such a sample, surface roughness scattering dominates the electron mobility, while for a sample without thermal treatment, both scatterings are important. Our theory provides a good quantitative explanation of the experimental data on electron transport, in particular, the different carrier-density dependences of the mobilities measured in O-polar face ZnO SFQWs prepared in different ways, by bombardment with H 2 + ions and by exposure to He + ions, which has not been explained so far.

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Section: Numerical Results and Comparison With Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electron mobility in Gaussian heavily doped ZnO surface quantum wells

2008

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“…5 doped with copper. It is the effect of the crystallographic orientation (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) of the sample [8,9]. On the sample No.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, surfaces with higher index orientation have regular atomic terraces or steps (the other samples in Figs. 2 and 3) ( [8,9] and [15]). …”

Section: Discussionmentioning

confidence: 99%

Substrates Grown from the Vapor for ZnO Homoepitaxy

et al. 2008

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The novel method of preparation of epi-ready ZnO substrates is demonstrated. The substrates were made of unique ZnO crystals grown by chemical vapor transport method using hydrogen as the transport agent. The effect of low-level doping (Mn, Co, Cu, and V) on the structural quality of the crystals was investigated. Atomic layer deposition was used to verify usability of the substrates for homoepitaxy. The thermal annealing prior to the atomic layer deposition process and effect of thermal annealing of the epitaxial layers was studied. The X-ray diffraction and atomic force microscopy methods were applied to study the structural quality of the ZnO layers. Detection of the dopants in the substrates by secondary ion mass spectroscopy made possible the measurement of the thickness of the layers. The obtained root mean square roughness for both the substrates and layers ranged between 0.2 nm and 5 nm, and was dependent on the sample crystallographic orientation and sequence of polishing and annealing procedures. The optimal recipe for the epi-ready substrate preparation was formulated.

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“…Later on, one found out other roughness-related scatterings, which are charge scattering, viz., fluctuations in the electron density distribution and dipole moments at the deformed interface, which are connected with bulk charges [7] and image potential [8]. Recent experimental investigations provided evidence for the poor quality of the ZnO surface [9,10,11] so that roughness-related scattering is of more importance. In Ref.…”

Section: Introductionmentioning

confidence: 99%

Scattering Mechanisms from Roughness-induced Fluctuations in Charge Distributions in ZnO Surface Quantum Wells

Туан

Tiên

et al. 2012

Comm. in Phys.

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We present a theoretical study of roughness-related scattering mechanisms for electrons in single heterostructures, especilaly in Gaussian-doped ZnO surface quantum wells. We show that besides the conventional scatterings there must exist roughness-related mechanisms of charge origin, which stem from fluctuations the electron density and the donor density in the bulk ZnO. The strength of the two charge-origin scattering sources is found to be comparable with the one of the standard one from fluctuations in the barrier position. The effect of the dielectric discontinuity on the scattering mechanisms is discussed.

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Effect of annealing atmosphere on the quality of ZnO crystal surface

Cited by 11 publications

References 10 publications

Electron mobility in Gaussian heavily doped ZnO surface quantum wells

Electron mobility in Gaussian heavily doped ZnO surface quantum wells

Substrates Grown from the Vapor for ZnO Homoepitaxy

Scattering Mechanisms from Roughness-induced Fluctuations in Charge Distributions in ZnO Surface Quantum Wells

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