Electronic structure of indium-tungsten-oxide alloys and their energy band alignment at the heterojunction to crystalline silicon

The electronic structure of thermally co-evaporated indium-tungsten-oxide films is investigated. The stoichiometry is varied from pure tungsten oxide to pure indium oxide, and the band alignment at the indium-tungsten-oxide/crystalline silicon heterointerface is monitored. Using in-system photoelectron spectroscopy, optical spectroscopy, and surface photovoltage measurements, we show that the work function of indium-tungsten-oxide continuously decreases from 6.3 eV for tungsten oxide to 4.3 eV for indium oxide, with a concomitant decrease in the band bending at the hetero interface to crystalline silicon than indium oxide.

[1]  D. Wood,et al.  High-mobility, sputtered films of indium oxide doped with molybdenum , 2004 .

[2]  S. Wenham,et al.  Characterisation of thermal annealed WOx on p-type silicon for hole-selective contacts , 2017 .

[3]  Claes-Göran Granqvist,et al.  Electrochromic tungsten oxide films: Review of progress 1993–1998 , 2000 .

[4]  M. Hermle,et al.  TCO work function related transport losses at the a-Si:H/TCO-contact in SHJ solar cells , 2014 .

[5]  A. Akl,et al.  Characterization of tungsten oxide films of different crystallinity prepared by RF sputtering , 2003 .

[6]  K. Heilig.  Determination of surface properties by means of large signal photovoltage pulses and the influence of trapping , 1974 .

[7]  P. Kościelniak,et al.  XPS and AFM studies of surface chemistry and morphology of In2O3 ultrathin films deposited by rheotaxial growth and vacuum oxidation , 2011 .

[8]  F. Ciuchi,et al.  Ellipsometry investigation of the effects of annealing temperature on the optical properties of indium tin oxide thin films studied by Drude–Lorentz model , 2009 .

[9]  Zheng-Hong Lu,et al.  Universal energy-level alignment of molecules on metal oxides. , 2011, Nature materials.

[10]  Gerald Earle Jellison,et al.  Erratum: ‘‘Parameterization of the optical functions of amorphous materials in the interband region’’ [Appl. Phys. Lett. 69, 371 (1996)] , 1996 .

[11]  Daniel Lincot,et al.  Buffer layers and transparent conducting oxides for chalcopyrite Cu(In,Ga)(S,Se)2 based thin film photovoltaics: present status and current developments , 2010 .

[12]  A. Javey,et al.  Efficient silicon solar cells with dopant-free asymmetric heterocontacts , 2016, Nature Energy.

[13]  P. Cabarrocas,et al.  Determination of the conduction band offset between hydrogenated amorphous silicon and crystalline silicon from surface inversion layer conductance measurements , 2008 .

[14]  B. Rech,et al.  Valence band alignment and hole transport in amorphous/crystalline silicon heterojunction solar cells , 2015 .

[15]  L. Korte,et al.  Direct determination of the band offset in atomic layer deposited ZnO/hydrogenated amorphous silicon heterojunctions from X-ray photoelectron spectroscopy valence band spectra , 2014 .

[16]  J. Yates,et al.  Band bending in semiconductors: chemical and physical consequences at surfaces and interfaces. , 2012, Chemical reviews.

[17]  Han‐Ki Kim,et al.  Effect of thickness and substrate temperature on the properties of transparent Ti-doped In2O3 films grown by direct current magnetron sputtering , 2013 .

[18]  R. Schropp,et al.  Growth Process Conditions of Tungsten Oxide Thin Films Using Hot-Wire Chemical Vapor Deposition , 2011 .

[19]  N. Koch,et al.  Ultrathin polythiophene films on an intrinsically conducting polymer electrode: Charge transfer induced valence states and interface dipoles , 2011 .

[20]  S. Harvey,et al.  Surface versus bulk electronic/defect structures of transparent conducting oxides: I. Indium oxide and ITO , 2006 .

[21]  T. Ma,et al.  High‐quality transparent conductive indium oxide films prepared by thermal evaporation , 1980 .

[22]  W. Kern,et al.  Chemical vapor deposition of transparent electrically conducting layers of indium oxide doped with tin , 1975 .

[23]  S. Glunz,et al.  Efficient carrier-selective p- and n-contacts for Si solar cells , 2014 .

[24]  B. E. Robertson,et al.  Purification, growth, structure, optical and electrical properties of single crystals of the π‐molecular complex of phenothiazine with pyromellitic dianhydride , 1980 .

[25]  L. Korte,et al.  Sputtered Tungsten Oxide as Hole Contact for Silicon Heterojunction Solar Cells , 2017, IEEE Journal of Photovoltaics.

[26]  C. Voz,et al.  Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells , 2016 .

[27]  Claes-Göran Granqvist,et al.  Spectroscopic ellipsometry characterization of electrochromic tungsten oxide and nickel oxide thin films made by sputter deposition , 2010 .

[28]  Frank Säuberlich,et al.  Transparent Conducting Oxides for Photovoltaics: Manipulation of Fermi Level, Work Function and Energy Band Alignment , 2010, Materials.

[29]  Su-Huai Wei,et al.  Effects of Ga addition to CuInSe2 on its electronic, structural, and defect properties , 1998 .

[30]  J. Han,et al.  Thermal atomic layer deposition of In2O3 thin films using dimethyl(N-ethoxy-2,2-dimethylcarboxylicpropanamide)indium and H2O , 2017 .

[31]  C. Voz,et al.  Origin of passivation in hole-selective transition metal oxides for crystalline silicon heterojunction solar cells , 2017 .

[32]  Philip Schulz,et al.  Interface energetics in organo-metal halide perovskite-based photovoltaic cells , 2014 .

[33]  J. Robertson,et al.  High-K materials and metal gates for CMOS applications , 2015 .

[34]  Hamid Reza Fallah,et al.  The effect of deposition rate on electrical, optical and structural properties of tin-doped indium oxide (ITO) films on glass at low substrate temperature , 2006 .

[35]  K. Lee,et al.  Work Function Modification of Tungsten-Doped Indium Oxides Deposited by the Co-Sputtering Method. , 2016, Journal of nanoscience and nanotechnology.

[36]  W. Tang,et al.  Transition Metal Oxide Work Functions: The Influence of Cation Oxidation State and Oxygen Vacancies , 2012 .

[37]  Yasushi Sato,et al.  Electrical and optical properties of amorphous indium zinc oxide films , 2006 .

[38]  Wolfgang Kowalsky,et al.  Transparent Inverted Organic Light‐Emitting Diodes with a Tungsten Oxide Buffer Layer , 2008 .

[39]  J. Ip,et al.  An X-ray photoelectron spectroscopy study of the interface formed between ITO and 4,4′-bis(4-dimethyl amino styryl)benzene based light emitting diode , 2003 .

[40]  L. Lozzi,et al.  Surface electronic properties of polycrystalline WO3 thin films: a study by core level and valence band photoemission , 2003 .

[41]  R. Grigorovici,et al.  Optical Properties and Electronic Structure of Amorphous Germanium , 1966, 1966.

[42]  Xien Liu,et al.  Nanostructure-based WO3 photoanodes for photoelectrochemical water splitting. , 2012, Physical chemistry chemical physics : PCCP.

[43]  Kazuhide Adachi,et al.  Amorphous indium tungsten oxide films prepared by DC magnetron sputtering , 2005 .

[44]  Jan Augustynski,et al.  Highly efficient water splitting by a dual-absorber tandem cell , 2012, Nature Photonics.

[45]  C. Ballif,et al.  Parasitic Absorption Reduction in Metal Oxide-Based Transparent Electrodes: Application in Perovskite Solar Cells. , 2016, ACS applied materials & interfaces.

[46]  Fan Zhang,et al.  Water splitting by tungsten oxide prepared by atomic layer deposition and decorated with an oxygen-evolving catalyst. , 2011, Angewandte Chemie.

[47]  M. Hermle,et al.  Molybdenum and tungsten oxide: High work function wide band gap contact materials for hole selective contacts of silicon solar cells , 2015 .

[48]  Xindong Zhang,et al.  Role of tungsten oxide in inverted polymer solar cells , 2009 .

[49]  B. Rech,et al.  Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells , 2016 .

[50]  Hui Shen,et al.  Fabrication and characterization of WO3 thin films on silicon surface by thermal evaporation , 2017 .

[51]  Liping Zhang,et al.  Improved opto-electronic properties of silicon heterojunction solar cells with SiOx/Tungsten-doped indium oxide double anti-reflective coatings , 2017 .

[52]  C. Battaglia,et al.  Silicon heterojunction solar cell with passivated hole selective MoOx contact , 2014 .

[53]  N. Park,et al.  Effects of Oxidation State and Crystallinity of Tungsten Oxide Interlayer on Photovoltaic Property in Bulk Hetero-Junction Solar Cell , 2012 .