EFFECTS OF HYDROGEN PLASMA TREATMENT ON OPTICAL, STRUCTURE AND BONDS PROPERTIES OF LSAT ((LaAlO3)0;3-(Sr2AlTaO6)0;7)

• Main Author: ROSARI PURBA (NIM : 10212008), DHIKA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/21701
• Institution: Institut Teknologi Bandung

Lanthanum Strontium Aluminium Tantalum Oksida or LSAT with molecular formula((LaAlO3)0;3-(Sr2AlTaO6)0;7) has great prominence as competitive single crystal substrate for the growth of epitaxial films of high-Tc superconductors due to its low dielectric response, exceptional crystallinity, cubic symmetry, and small lattice constant. In this study, <br /> <br /> <br /> the effects of hydrogen-plasma treatment on the optical and structural properties of LSAT were investigated by various techniques of characterization. LSAT substrate being exposed to remote hydrogen plasma at room temperature for 10 minutes. Optical properties of material LSAT based on spectroscopy ellipsometry (SE) have not been report completely. The optical transmission was measured by SE with the energy 1-6.4 ev. Determination of the lattice parameters and the phase identification obtained crystals by X-ray diffraction analysis, the result showed that LSAT has cubic structure with lattice parameters a = 3.89244 (symbol)A. The topographic images taken before and after H2 plasma treatment with Atomic Force Microscopy that showed the roughness of LSAT was reduced by hydrogen plasma exposure. The functional groups were investigated by FTIR and Raman shows that Al-O bonds vanished and there are dissapeareace of O-H bonds and Al-O broad. From of spectroscopy ellipsometry we have found that there is decrease in optical band gap of LSAT from 5 eV to 4,85 eV and hydrogen plasma treatment can increase optical <br /> <br /> <br /> conductivity, carrier concentration and absorption coefficient because creation of oxygen vacancy that liberates two electrons therefore increasing the overall carrier concentration of LSAT.