16:45 〜 17:00
▲ [10p-S203-15] Electrochemical Control of the Optoelectronic Properties of La-doped BaSnO3 Epitaxial Films using YSZ as the Solid Electrolyte
キーワード：optoelectronic properties, transparent oxide semiconductor, electrochemical control
Introduction
La-doped BaSnO3 (LBSO) has attracted increasing attention as the transparent conducting oxide because it shows relatively high carrier mobility (~300 cm2 V−1 s−1 for bulk single crystals, ~150 cm2 V−1 s−1 for epitaxial films) and high activation efficiency of La-dopant. In our previous study, we found that Sn2+ formation occurs at the beginning of the LBSO film growth and therefore mobility of LBSO film is suppressed when the film is thin. Further, we successfully improved the mobility by increasing the oxidation atmosphere during the LBSO film growth. In this study, we controlled the oxidation degree of the LBSO films after the film growth electrochemically by using YSZ as the solid electrolyte. As a result of this study, we successfully controlled the optoelectronic properties of the LBSO films.
Experimental
3% La-doped BaSnO3 films were heteroepitaxially grown on (001) YSZ single crystal substrate by pulsed laser deposition (PLD) method. Then, the film was electrochemically reduced by applying positive electric voltage (+3 V) to the YSZ substrate at 300 °C in air.
Results and discussion
The as-grown LBSO film was transparent. After the reduction treatment, the color of the reduced LBSO film changed to brown because of the divalent tin ions generated during the electrochemical reduction process. As shown in the Figure, the as-grown film has almost zero absorption in the visible light range, whereas the reduced film absorbs exceed 40% of the light in the entire visible light range. Simultaneously, the electrical resistivity decreased from 0.5 to 0.02 Ω cm. The present results indicated that optoelectronic properties of the LBSO films could be modulating by electrochemical method, providing a new inspiration for designing LBSO-based optoelectronic device.
La-doped BaSnO3 (LBSO) has attracted increasing attention as the transparent conducting oxide because it shows relatively high carrier mobility (~300 cm2 V−1 s−1 for bulk single crystals, ~150 cm2 V−1 s−1 for epitaxial films) and high activation efficiency of La-dopant. In our previous study, we found that Sn2+ formation occurs at the beginning of the LBSO film growth and therefore mobility of LBSO film is suppressed when the film is thin. Further, we successfully improved the mobility by increasing the oxidation atmosphere during the LBSO film growth. In this study, we controlled the oxidation degree of the LBSO films after the film growth electrochemically by using YSZ as the solid electrolyte. As a result of this study, we successfully controlled the optoelectronic properties of the LBSO films.
Experimental
3% La-doped BaSnO3 films were heteroepitaxially grown on (001) YSZ single crystal substrate by pulsed laser deposition (PLD) method. Then, the film was electrochemically reduced by applying positive electric voltage (+3 V) to the YSZ substrate at 300 °C in air.
Results and discussion
The as-grown LBSO film was transparent. After the reduction treatment, the color of the reduced LBSO film changed to brown because of the divalent tin ions generated during the electrochemical reduction process. As shown in the Figure, the as-grown film has almost zero absorption in the visible light range, whereas the reduced film absorbs exceed 40% of the light in the entire visible light range. Simultaneously, the electrical resistivity decreased from 0.5 to 0.02 Ω cm. The present results indicated that optoelectronic properties of the LBSO films could be modulating by electrochemical method, providing a new inspiration for designing LBSO-based optoelectronic device.