The influence of ion bombardment and annealing on the conductivity of thepolar ZnO surface

Margoninski, Y.; Егер, Д.

doi:10.1016/0039-6028(79)90720-9

Cited by 11 publications

(3 citation statements)

References 9 publications

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“…Adsorption of atomic hydrogen or oxygen results in a strong variation of the sheet conductance of cleaved polar surfaces 5 which was assigned to the variation of the direction of band bending due to the donor/acceptor character of H/O that switches the space charge layer from an accumulation (H exposure) to a depletion (O 2 exposure) region. The accumulation zone with a carrier density of 10 12 − 10 13 cm −2 can be produced by atomic H 6,[29][30][31][32][33][34][35][36] , plasma exposure 37 , ion-bombardment or H + 2 implantation 38,39 , or on asreceived substrates 40 and after hydroxylation 35,41 . The increase in carrier concentration in the accumulation layer was correlated (i) to a variation of the band bending that induces quasi-bidimensional confined trapped states 29,[33][34][35][36]42 and (ii) to a decrease in work function.…”

Section: Introductionmentioning

confidence: 99%

Band alignment at Ag/ZnO(0001) interfaces: A combined soft and hard x-ray photoemission study

et al. 2018

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Band alignment at the interface between evaporated silver films and Zn-or O-terminated polar orientations of ZnO is explored by combining soft and hard X-ray photoemissions on native and hydrogenated surfaces. Ultraviolet Photoemission Spectroscopy (UPS) is used to track variations of work function, band bending, ionization energy and Schottky barrier during silver deposition.The absolute values of band bending and the bulk position of the Fermi level are determined on continuous silver films by HArd X-ray PhotoEmission Spectroscopy (HAXPES) through a dedicated modeling of core levels. Hydrogenation leads to the formation of ∼ 0.3 monolayer of donor-like hydroxyl groups on both ZnO-O and ZnO-Zn surfaces and to the release of metallic zinc on ZnO-Zn. However no transition to an accumulation layer is observed. On bare surfaces, silver adsorption is cationic on ZnO(0001)-O (anionic on ZnO(0001)-Zn) at the earliest stages of growth as expected from polarity healing before adsorbing as a neutral species. UPS and HAXPES data appear quite consistent. The two surfaces undergo rather similar band bendings for all types of preparation. The downward band bending of V bb,ZnO−O = −0.4 eV and V bb,ZnO−Zn = −0.6 eV found for the bare surfaces are reinforced for upon hydrogenation (V bb,ZnO−O+H = −1.1 eV, V bb,ZnO−Zn+H = −1.2 eV). At the interface with Ag, a unique value of band bending of -0.75 eV is observed. While exposure to atomic hydrogen modulates strongly the energetic positions of the surface levels, a similar Schottky barrier of 0.5-0.7 eV is found for thick silver films on the two surfaces.

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Section: Introductionmentioning

confidence: 99%

Band alignment at Ag/ZnO(0001) interfaces: A combined soft and hard x-ray photoemission study

et al. 2018

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“…Previously, an increase in conductivity upon ion beam sputtering was observed for ZrO single crystals by Margoninski and Eger. 40 They explained that the defect states created by the sputtering increased the conductivity. We believe that the mechanism of conductivity increase might be similar.…”

Section: B Bcocmentioning

confidence: 99%

Charge transfer from Cu in YBa2Cu3O7−δ and Ba2Cu3O4Cl2 crystals determined by Auger electron spectroscopy

Ogawa¹,

Noro²,

Maki³

1997

Journal of Applied Physics

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A formulation is proposed to estimate the charge transfer ΔqCu from Cu to some anions in metal-oxide crystals, using Auger electron spectroscopy. In the formulation, a parameter, the Auger transition probability ω, is introduced, which is defined as the ratio of Auger intensity due to a certain transition to the total Auger intensity due to other transitions when the same core electrons are primarily excited. By applying the formulation to vacuum-cleaved surfaces of YBa2Cu3O7−δ (YBCO) and Ba2Cu3O4Cl2 (BCOC) crystals, we obtained the following results: (1) YBCO cleaves between CuO2 and BaO layers, and the amount of ΔqCu is 2.3 in units of elementary electric charge. The deviation of ΔqCu from 2.0 suggests the existence of Cu3+-like atoms; (2) for BCOC, ΔqCu varies from 3.3 to 1.7 depending on the Ar ion beam sputtering time.

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“…Supposedly, a number of surface states are created on the ZnO surface by bombardment with the accelerated ions or electrons ejected from plasma. 21) The following oxygen absorption may lead to the capture of electrons distributing near the surface, resulting in the formation of a depletion layer.…”

mentioning

confidence: 99%

High-Mobility Field-Effect Transistors Based on Single-Crystalline ZnO Channels

Nishii¹,

Ohtomo²,

Ohtani³

et al. 2005

Jpn. J. Appl. Phys.

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We have fabricated field-effect transistors with single-crystalline ZnO channels consisting of high-quality epitaxial films grown on lattice-matched (0001) ScAlMgO4 substrates by laser molecular-beam epitaxy. Amorphous alumina gate insulators are deposited on the top of the ZnO films using either RF magnetron sputtering or electron-beam evaporation. The field-effect mobility (µFE) of the device prepared by the latter method is as high as 40 cm2·V-1·s-1, one order of magnitude higher than those typically observed for polycrystalline channel devices. However, hysteresis appears in transfer characteristics. This unfavorable effect is found to be eliminated by the thermal annealing of the entire devices in air. The much larger hysteresis and lower µFE are observed for the device with sputtered gate insulators. This is presumably due to dense surface states created by ion or electron bombardment during the sputtering.

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The influence of ion bombardment and annealing on the conductivity of thepolar ZnO surface

Cited by 11 publications

References 9 publications

Band alignment at Ag/ZnO(0001) interfaces: A combined soft and hard x-ray photoemission study

Band alignment at Ag/ZnO(0001) interfaces: A combined soft and hard x-ray photoemission study

Charge transfer from Cu in YBa2Cu3O7−δ and Ba2Cu3O4Cl2 crystals determined by Auger electron spectroscopy

High-Mobility Field-Effect Transistors Based on Single-Crystalline ZnO Channels

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