16:45 〜 17:00
▼ [12p-N206-14] Single-Crystalline La:SrSnO3 Conductive Sheet with Wide Bandgap of 4.4 eV
キーワード：conductive sheet, transparent oxide semiconductor, wide bandgap
Transparent conductive oxides (TCOs) are important for optoelectronic devices. Currently, ITO is widely used as TCO due to its high electrical conductivity and easy synthesis. However, its bandgap is small compared to the requirements of electrodes for deep ultra violet light-emitting-diode (DUV-LED: hν > 4.1 eV). One promising candidate for electrode of DUV-LED is La-doped SrSnO3 (LSSO) due to its both wide bandgap and high electrical conductivity. However, since the growth of high-quality LSSO film requires high substrate temperature, the device itself will be damaged if LSSO films are directly fabricated on the device. To solve the problem, here, we proposed a lift-off and transfer method for the application of LSSO. Through the method, the LSSO single-crystalline sheet with lateral size of 5 mm × 5 mm was successfully obtained without cracks at room temperature.
The 300-nm-thick LSSO single-crystalline thin film was grown on the water-soluble Sr3Al2O6 (SAO) buffered SrTiO3 substrate by PLD method. We removed the SAO layer with water. The LSSO sheet was further transferred on glass or PET substrates.
Figures 1(a) and 1(b) show the out-of-plane XRD patterns of the LSSO/SAO bilayer film and transferred LSSO sheet, respectively. Both the XRD patterns clearly exhibited the LSSO peaks without any impurity peaks. Single crystallinity of the sheet was confirmed by RSM measurement. Figure 1(c) shows the photograph of transferred LSSO sheet with a lateral size of as large as 5 mm × 5 mm. In all the area, no cracks were observed. In addition, the sheet exhibited coexistence of high electrical conductivity (~1300 S cm−1) and wide bandgap (~4.4 eV) at room temperature. These results indicated that LSSO sheets are good candidate for an electrode material of the DUV-LED. Furthermore, the STO substrate for bilayer film deposition could be reused, showing the usability of the synthesis process.
The 300-nm-thick LSSO single-crystalline thin film was grown on the water-soluble Sr3Al2O6 (SAO) buffered SrTiO3 substrate by PLD method. We removed the SAO layer with water. The LSSO sheet was further transferred on glass or PET substrates.
Figures 1(a) and 1(b) show the out-of-plane XRD patterns of the LSSO/SAO bilayer film and transferred LSSO sheet, respectively. Both the XRD patterns clearly exhibited the LSSO peaks without any impurity peaks. Single crystallinity of the sheet was confirmed by RSM measurement. Figure 1(c) shows the photograph of transferred LSSO sheet with a lateral size of as large as 5 mm × 5 mm. In all the area, no cracks were observed. In addition, the sheet exhibited coexistence of high electrical conductivity (~1300 S cm−1) and wide bandgap (~4.4 eV) at room temperature. These results indicated that LSSO sheets are good candidate for an electrode material of the DUV-LED. Furthermore, the STO substrate for bilayer film deposition could be reused, showing the usability of the synthesis process.