Absorption edge shift in ZnO thin films at high carrier densities

Roth, A. P.; Webb, J. B.; Williams, D. F.

doi:10.1016/0038-1098(81)90224-6

Cited by 166 publications

(72 citation statements)

References 13 publications

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“…The film of ZnO:Al (465 nm) showed an increase in the gap to around 3.47 eV. This increase is related to the Moss Burstein effect 23,24 . When the number of critical charge carriers is exceeded in a n-type semiconductor, the Fermi level moves toward the conduction band by filling its lower states.…”

Section: Resultsmentioning

confidence: 94%

“…When the number of critical charge carriers is exceeded in a n-type semiconductor, the Fermi level moves toward the conduction band by filling its lower states. Consequently an extension of the optical gap occurs and a higher excitation energy will be required for an electronic transition from the valence band to an unoccupied state of the conduction band 23,24 . The shift of the Fermi level to the conduction band can be described by Equation 4 23 .…”

Section: Resultsmentioning

confidence: 99%

“…where * c m is the effective mass of conduction, which for ZnO is equal to 0.38 [23] , h is Planck's constant, and N is the carrier density. Therefore, the carrier density of the doped film can be obtained knowing that the energy variation (∆E N ) between the intrinsic ZnO film (3.28 eV) and the doped film (3.47 eV) is equal to 0.19 eV.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the carrier density of the doped film can be obtained knowing that the energy variation (∆E N ) between the intrinsic ZnO film (3.28 eV) and the doped film (3.47 eV) is equal to 0.19 eV. It is known that the intrinsic ZnO film has a carrier density of 5.9 × 10 18 cm -3 [23] , and with doping the carrier density of the ZnO:Al film increases to 8.8 × 10…”

Section: Resultsmentioning

confidence: 99%

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Morphological and electrical evolution of ZnO: Al thin filmsdeposited by RF magnetron sputtering onto glass substrates

et al. 2014

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Morphological and electrical evolution of ZnO: Al thin filmsdeposited by RF magnetron sputtering onto glass substrates

et al. 2014

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“…In undoped ZnO, for carrier concentrations higher than 3 to 5 × 10 19 cm −3 , the merging of the impurity band (originally giving rise to the Burstein Moss behavior) with the conduction band occurs, causing a change in the electrical transport properties of ZnO from semiconductor to metal behavior at RT [37]. Tables 2 and 3 show that the electron density measured in the Nd-doped films are often higher than this critical density, and thus a metallic behavior is expected for these films.…”

Section: Resultsmentioning

confidence: 99%

Transparent conductive Nd-doped ZnO thin films

Nistor¹,

Millon²,

Cachoncinlle³

et al. 2015

J. Phys. D: Appl. Phys.

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Any correspondence concerning this service should be sent to the repository Administrator : archiveouverte@ensam.eu IntroductionDue to its specific electrical and optical properties (high electrical conductivity and high optical transparency in the visible domain), zinc oxide (ZnO) is a suitable material with applications in a large number of devices and components such as optical waveguides, piezoelectric transducers, transparent conductive electrodes, gas sensors, light emitting diodes, and others [1][2][3][4][5][6]. Moreover, because it is abundant and environmentally friendly, ZnO is an ideal wide bandgap material for applications in photovoltaics (PV). The ability to easily tune the conductivity, charge carrier concentration, and optical properties of ZnO films is highly desirable for these applications. Doping by well-suited elements is a way to modify or enhance physical properties or to induce new ones in oxide films [5][6][7][8][9]. In this frame, the best doping of ZnO thin films for both electrical conductivity and optical transparency comparable with those of the indium-tin oxide ( AbstractTransparent Nd-doped ZnO films with thickness in the range of 70 to 250 nm were grown by pulsed-laser deposition (PLD) on c-cut sapphire substrates at various oxygen pressures and substrate temperatures. A wide range of optical and electrical properties of the films were obtained and correlated to the composition and crystalline structure. The Nd-doped ZnO films are smooth, dense, and display the wurtzite phase. Different epitaxial relationships between films and substrate as a function of growth pressure and substrate temperature were evidenced by asymmetric x-ray diffraction measurements. By varying PLD growth conditions, the films can be tuned to have either metallic or semiconductor characteristics, with good optical transmittance in the visible range. Moreover, a low-temperature metal-insulator transition may be observed in Nd-doped ZnO films grown under low oxygen pressure. Resistivities as low as 6 × 10 −4 Ω cm and 90% optical transmittance in the visible range and different nearinfrared transmittance are obtained with approximately 1.0-1.5 at.% Nd doping and growth temperature of approximately 500 °C.

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Indium-doped zinc oxide films prepared by simultaneous r.f. and d.c. magnetron sputtering

Zhang

Zhu

Huan

et al. 1999

Surf. Interface Anal.

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Indium‐doped zinc oxide (ZnO:In) films were prepared by simultaneous r.f. and d.c. magnetron sputtering. The structural, optical and electrical properties of the films have been obtained by x‐ray diffractometry (XRD), Rutherford backscattering spectrometry (RBS), spectrophotometry and atomic force microscopy (AFM) together with four‐point probe measurements. The XRD pattern shows ZnO(002) to be the preferred film orientation. The deposited In/Zn atomic ratio is ∼0.4. Uniform ZnO:In films with a resistivity of ∼7 × 10−4 Ω.cm and a high transparency (>85%) were achieved, with further optimization possible. Copyright © 1999 John Wiley & Sons, Ltd.

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Absorption edge shift in ZnO thin films at high carrier densities

Cited by 166 publications

References 13 publications

Morphological and electrical evolution of ZnO: Al thin filmsdeposited by RF magnetron sputtering onto glass substrates

Morphological and electrical evolution of ZnO: Al thin filmsdeposited by RF magnetron sputtering onto glass substrates

Transparent conductive Nd-doped ZnO thin films

Indium-doped zinc oxide films prepared by simultaneous r.f. and d.c. magnetron sputtering

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