| 초록 |
We made 2-dimensional electron gas using SrTiO3/(Sr1-x,Lax)TiO3 superlattice. In this work, La doped SrTiO3 superlattices, i.e., SrTiO3/(Sr1-x,Lax)TiO3 superlattices (STO/SLTO), have been deposited onto stepped-SrTiO3 substrate using laser-molecular beam epitaxy (Laser-MBE). In SrTiO3/(Sr1-x,Lax)TiO3 superlattice, the stacking sequence of superlattice was varied from (STO)2 unit cell/(SLTO)2 unit cell to (STO)12 unit cell/(SLTO)2 unit cell. The stacking sequence was in situ monitored by reflection high energy electron diffraction (RHEED) specular spot intensity oscillation. The layer-by-layer growth mode of STO/SLTO superlattice was also confirmed by RHEED intensity oscillation and atomic force microscopy (AFM). Using this technique, we controlled the defect distribution in 2-dimensional way. The electrical properties of STO/SLTO superlattice showed different behavior from SLTO thin films. The 2-dimensional defect distribution generates the divergence of polarization. Therefore, we discuss the 2-dimensional transport properties in terms of the charge screening process due to divergence of polarization. |
