Morphological, optical and electrical properties of GaSe sub(9) films and its application in photovoltaic devices

We report on the characterization of crystalline GaSe sub(9) thin films produced by thermal evaporation onto fluorine doped tin oxide (FTO) transparent electrode substrate, and its further application in photovoltaic devices. The physical properties are studied in order to understand the implication...

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Bibliographic Details
Published in:Journal of materials science. Materials in electronics 2017-01, Vol.28 (2), p.2241-2249
Main Authors: Hoff, Anderson, Cruz-Cruz, Isidro, Siqueira, Mariana C, Machado, Kleber D, Huemmelgen, Ivo A
Format: Article
Language:English
Subjects:
Crystal structure
Devices
Electrodes
Electronics
Gallium
Impedance spectroscopy
Photovoltaic cells
Solar cells
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Summary:We report on the characterization of crystalline GaSe sub(9) thin films produced by thermal evaporation onto fluorine doped tin oxide (FTO) transparent electrode substrate, and its further application in photovoltaic devices. The physical properties are studied in order to understand the implications of gallium addition to the Se alloy. Hexagonal structure of the crystalline films after thermal annealing is confirmed by X-ray diffraction, whereas scanning electron microscopy images indicate improved morphology in GaSe sub(9) films, in comparison to Se films. Photoelectrical properties of the devices are studied by current density-voltage, capacitance-voltage and impedance spectroscopy measurements. GaSe sub(9) based devices show average power conversion efficiency of 1.37 %, under 100 mW/cm super(2) AM 1.5 irradiance, in a simple FTO/GaSe sub(9)/Au structure. It means an increase of 40 % with respect to Se devices under the same structure. Additional improvements are related with the built-in potential, charge carrier concentration and depletion width, which are derived by the Schottky-Mott relationship. Finally, from impedance spectroscopy measurements, an increase in the recombination time and a faster charge extraction in GaSe sub(9)-based devices are observed.
ISSN:0957-4522
1573-482X
DOI:10.1007/s10854-016-5794-5