10:15 〜 10:30
▲ [26a-E202-5] [The 51st Young Scientist Presentation Award Speech] Single-Crystalline La:SrSnO3 Conductive Sheet with Wide Bandgap of 4.6 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 (~3.5 eV [1]) 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 an electrode of DUV-LED is La-doped SrSnO3 (LSSO) due to its both wide bandgap (~4.6 eV) and high electrical conductivity (~3000 S cm−1). [2] However, since the growth of high-quality LSSO film requires high substrate temperature (~750 °C), 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.
Figures 1(a) and 1(b) show the out-of-plane X-ray diffraction (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 reciprocal space mapping 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 (~1600 S cm−1) and wide bandgap (~4.6 eV) at room temperature. These results indicated that LSSO sheets are good candidate for an electrode material for the DUV-LED. Furthermore, the STO substrate for bilayer film deposition could be reused, showing the usability of the synthesis process.
Figures 1(a) and 1(b) show the out-of-plane X-ray diffraction (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 reciprocal space mapping 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 (~1600 S cm−1) and wide bandgap (~4.6 eV) at room temperature. These results indicated that LSSO sheets are good candidate for an electrode material for the DUV-LED. Furthermore, the STO substrate for bilayer film deposition could be reused, showing the usability of the synthesis process.