Growth of SrVO3 thin films by hybrid molecular beam epitaxy

Abstract

The authors report the growth of stoichiometric SrVO3 thin films on (LaAlO3)0.3(Sr2AlTaO6)0.7 (001) substrates using hybrid molecular beam epitaxy. This growth approach employs a conventional effusion cell to supply elemental A-site Sr and the metalorganic precursor vanadium oxytriisopropoxide (VTIP) to supply vanadium. Oxygen is supplied in its molecular form through a gas inlet. An optimal VTIP:Sr flux ratio has been identified using reflection high-energy electron-diffraction, x-ray diffraction, atomic force microscopy, and scanning transmission electron microscopy, demonstrating stoichiometric SrVO3 films with atomically flat surface morphology. Away from the optimal VTIP:Sr flux, characteristic changes in the crystalline structure and surface morphology of the films were found, enabling identification of the type of nonstoichiometry. For optimal VTIP:Sr flux ratios, high quality SrVO3 thin films were obtained with smallest deviation of the lattice parameter from the ideal value and with atomically smooth surfaces, indicative of the good cation stoichiometry achieved by this growth technique.

Unleashing Strain Induced Ferroelectricity in Complex Oxide Thin Films via Precise Stoichiometry Control

“…An adsorption controlled growth window for SrTiO 3 films was accessed at growth temperatures of ~800 °C . Similar growth windows have been recently reported for NdTiO 3 , GdTiO 3 , BaTiO 3 , and BaSnO 3 , as well as vanadate systems such as SrVO 3 , and LaVO 3 , using metal–organic vanadium(V) oxytriisopropoxide. Using the hybrid MBE approach, record high electron mobilities >50 000 cm 2 V –1 s –1 in La‐doped SrTiO 3 films have been reported, device quality factors of Q = 1/tan(δ) >1000 in Ba x Sr 1– x TiO 3 were achieved, and record high residual resistivity ratios, ρ 300K /ρ 5K , in metal SrVO 3 films were recently demonstrated, exceeding bulk single crystal values .…”

High Carrier Mobility, Electrical Conductivity, and Optical Transmittance in Epitaxial SrVO3 Thin Films

“…For instance, SrVO 3 (SVO) single crystals are known to be metallic and early reports also indicated than the metallic character was preserved in thin films . Progress on SVO thin film growth have been achieved by using pulsed laser deposition (PLD), hybrid molecular beam epitaxy (hybrid‐MBE), and pulsed e‐beam deposition (PED) . The metallic character of SVO, associated to its intrinsically large carrier density of about 10 22 cm −3 , combined with the strongly correlated behavior of electrons in the 3d‐band, which give rise to a large effective mass, should allow to reduce the plasma frequency from the ultraviolet (as in common metals) down to the visible or near infrared regions.…”

Surface Characterizations and Selective Etching of Sr‐Rich Segregation on Top of SrVO3 Thin‐Films Grown by Pulsed Laser Deposition

“…An optimized and competitive SrVO 3 (SVO) thin‐film is characterized by two factors, a stoichiometric cationic ratio Sr/V equal to 1 and a high relative resistivity ratio (RRR) which is the ratio of electrical resistivity at room temperature (300 K) and the one at low temperature (2 K). State of the art SVO thin‐films grown by pulsed laser deposition (PLD) onto SrTiO 3 (STO) (100) have a RRR of 2.4, which is much lower compared to hybrid‐MBE deposition technique ,. Since PLD is a most common technique for complex oxides, process conditions to perform an efficient SVO thin‐film are taken under strong interest ,,.…”

“…State of the art SVO thin-films grown by pulsed laser deposition (PLD) onto SrTiO 3 (STO) (100) have a RRR of 2.4, [10] which is much lower compared to hybrid-MBE deposition technique. [9,[20][21][22] Since PLD is a most common technique for complex oxides, [23][24][25] process conditions to perform an efficient SVO thin-film are taken under strong interest. [6,26,27] In this regard, oxygen is particularly known as a crucial parameter leading for instance to the creation of a Metal Insulator Transition (MIT) in other perovskite compounds for STO, [28][29][30] and LaNiO 3 .…”