Characterization of tungsten oxide films of different crystallinity prepared by RF sputtering

Tungsten oxide (WO x ) can be incorporated into amorphous/crystalline silicon heterojunction solar cells as hole contact and for interface modification between p-type amorphous silicon and indium tin oxide. This paper aims at understanding the influence of tungsten oxides properties on silicon heterojunction solar cells. Using in-system photoelectron spectroscopy on thermally evaporated WO x layers, it was verified that WO x with a stoichiometry close to WO 3 features a work function close to 6 eV and is therefore suitable as hole contact on silicon. Additionally the oxygen vacancy concentration in WO x was measured using photoelectron spectroscopy. High oxygen vacancy concentrations in WO x lead to a low band bending in the WO x /silicon-junction. Furthermore solar cells were fabricated using the same WO x , and the band bending in these cells is correlated with their fill factors (FF) and open circuit voltages (V OC ).Combining these results, the following picture arises: Positively charged oxygen vacancies raise the Fermi-level in WO x and reduce the band bending at the WO x /silicon-junction. This, in turn, leads to reduced V OC and FF. Thus, when incorporating WO x into silicon solar cells it is important to minimize the oxygen vacancy density in WO x . Therefore deposition methods, enabling adjustment of the WO x stoichiometry are preferable.

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“…Therefore different methods for it's deposition like reactive sputtering [32] and chemical vapor deposition [33] should be employed.…”

Section: Solar Cell Resultsmentioning

confidence: 99%

Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells

Mews

Korte

Rech

2016

Solar Energy Materials and Solar Cells

141

105

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“…The general decrease of the resistivity with substrate temperature may be explained by assuming the two-phase model [25,26]. According to this model, the films material consists of nano-crystalline phase D30 nm crystal size, dispersed in amorphous matrix.…”

Section: Article In Pressmentioning

confidence: 99%

Characterization of nickel oxide films deposited at different substrate temperatures using spray pyrolysis

Kamal

Elmaghraby

Ali

et al. 2004

Journal of Crystal Growth

128

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“…These films can be amorphous or polycrystalline depending on preparation method. These films have previously been deposited by various different techniques such as sputtering [7][8][9][10], pulsed laser [11,12], thermal evaporation [13][14][15], wet chemical method [16][17][18][19][20][21], sol-gel [22], and spray pyrolysis [23,24]. However, the properties of the films are significantly affected by the film crystallinity.…”

Section: Introductionmentioning

confidence: 99%

Electrical conductivity and dielectric relaxation in non-crystalline films of tungsten trioxide

Hutchins

Abu-Alkhair

El-Nahass

et al. 2007

Journal of Non-Crystalline Solids

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Characterization of tungsten oxide films of different crystallinity prepared by RF sputtering

Cited by 49 publications

References 25 publications

Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells

Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells

Characterization of nickel oxide films deposited at different substrate temperatures using spray pyrolysis

Electrical conductivity and dielectric relaxation in non-crystalline films of tungsten trioxide

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