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Evolution of Optical, Electrical, and Structural Properties of Indium Tungsten Oxide upon High Temperature Annealing
Author(s) -
Menzel Dorothee,
Korte Lars
Publication year - 2020
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.202000165
Subject(s) - annealing (glass) , materials science , crystallization , indium , oxide , tungsten , stoichiometry , conductivity , analytical chemistry (journal) , thin film , electrical resistivity and conductivity , tungsten compounds , transparent conducting film , chemical engineering , metallurgy , nanotechnology , chemistry , electrical engineering , chromatography , engineering
Optical, structural and electrical properties of thermally co‐evaporated indium tungsten oxide (IWO x ) thin films with varied stoichiometry, from pure tungsten oxide to pure indium oxide (InO x ) are investigated upon stepwise annealing, up to 700 °C. The thin films are candidate materials for carrier selective contacts in different types of solar cells, such as silicon hetero junction and perovskite solar cells. Three different phases for the thin films with different stoichiometry and crystallization temperatures of T c > 500 °C for tungsten‐rich layers and T c ≈ 200 °C for indium‐rich layers are found. The pronounced optical absorption of the as‐deposited InO x ‐rich layers is strongly decreased after crystallization. Tungsten oxide rich layers show low optical absorption in the as‐deposited state as well as for all applied annealing temperatures. The lateral conductivity of the pure indium oxide can be increased from 1.24 × 10 −2 up to 0.83 S cm −1 after 700 °C annealing. The conductivity of the pure tungsten oxide increases slightly after crystallization from 2.55 × 10 −5 to 8.25 × 10 −5 S cm −1 after annealing at 700 °C. However, for mixed oxide layers with ≈25% InO x ‐fraction in the mixture, the highest conductivity of 4.0 × 10 −6 S cm −1 cannot be increased by the applied annealing process.