Improved electrical mobility in highly epitaxial La:BaSnO3 films on SmScO3(110) substrates

Abstract

Heteroepitaxial growth of BaSnO3 and Ba1−xLaxSnO3 (x = 7%) lanthanum doped barium stannate thin films on different perovskite single crystal (SrTiO3 (001) and SmScO3 (110)) substrates has been achieved by pulsed laser deposition under optimized deposition conditions. X-ray diffraction measurements indicate that the films on either of these substrates are relaxed due to the large mismatch and present a high degree of crystallinity with narrow rocking curves and smooth surface morphology while analytical quantification by proton induced X-ray emission confirms the stoichiometric La transfer from a polyphasic target, producing films with measured La contents above the bulk solubility limit. The films show degenerate semiconducting behavior on both substrates, with the observed room temperature resistivities, Hall mobilities, and carrier concentrations of 4.4 mΩ cm, 10.11 cm2 V−1 s−1, and 1.38 × 1020 cm−3 on SmScO3 and 7.8 mΩ cm, 5.8 cm2 V−1 s−1, and 1.36 × 1020 cm−3 on SrTiO3 ruling out any extrinsic contribution from the substrate. The superior electrical properties observed on the SmScO3 substrate are attributed to reduction in dislocation density from the lower lattice mismatch.

Oxygen vacancy-assisted recovery process for increasing electron mobility in n-type BaSnO3 epitaxial thin films

“…This low μ e has been attributed to the abundance of TDs 9 that inevitably form during epitaxial growth due to large lattice mismatch with the substrate, e.g., SrTiO 3 or MgO. Therefore, considerable effort has been devoted to decreasing the density of TDs by using substrates with a lattice constant that is similar to or even the same as that of BSO [13][14][15][16] or by inserting buffer layers between BSO epilayers and typical substrates 12,[17][18][19] to release the lattice mismatch strain.…”

High-mobility BaSnO3 grown by oxide molecular beam epitaxy

“…3. (a) µ at 300 K as a function of n 3D for BaSnO 3 films grown on SrTiO 3 and PrScO 3 using oxide MBE (this work), and from reports from the literature (Kim et al, 12 Ganguly et al, 9 and Wadekar et al 11 ). The thickness of all films is 32 nm, except for one film on SrTiO 3 (starred), which was 64 nm.…”

Transparent conducting properties of SrSnO3 and ZnSnO3

“…These include the fact that it is In free. [6][7][8][9][10][11][12] Here, we investigate the related compounds, n-type SrSnO 3 and ZnSnO 3 , which have smaller lattice parameters, more compatible with common oxide electronic substrates.…”

“…This material, which has a simple s-band electronic structure, 17,[19][20][21][22][23][24] is dopable to a highly conductive state using Sb or La, 25 and has been developed as a high performance TCO. [6][7][8][9][10][11][12] The related compounds, CaSnO 3 and SrSnO 3 , occur in distorted orthorhombic perovskite structures, 26 while ZnSnO 3 occurs in a ferroelectric LiNbO 3 type structure. 13,[27][28][29][30] Amorphous zinc-tin-oxide amorphous films were already been successfully developed for transparent electronics ten years ago, 31 while mixed phase films with compositions near ZnSnO 3 are known to show good TCO properties.…”