Combined spectroscopy and electrical characterization of La:BaSnO3 thin films and heterostructures

Tchiomo, Arnaud P. Nono; Carleschi, Emanuela; Prinsloo, A. R. E.; Sigle, Wilfried; Aken, Peter A. van; Mannhart, J.; Ngabonziza, Prosper; Doyle, Bryan P.

doi:10.1063/5.0105116

Cited by 4 publications

(1 citation statement)

References 84 publications

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“…On the other hand, the position of the VBM in BSLO with respect to the Fermi level is found E VBM ≈ −3.2 eV (Fig. S6.5 within the Supplemental Material [17]), which is a good agreement with earlier reports [50,51] and the indirect gap determined from optical measurements [38,39]. Using these values, the experimentally determined band alignment is shown in Fig.…”

Section: Lsmo/lfo/blsosupporting

confidence: 88%

Band Alignment and Photoresponse of LaFeO3 -Based Heterojunctions

et al. 2023

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Epitaxial LaFeO 3 (LFO)-based photocells, of different thicknesses (50-200 nm) have been grown on cubic LSAT (001) [(LaAlO 3 ) 0.3 (Sr 2 TaAlO 6 ) 0.7 ] single-crystal substrates, using a La 2/3 Sr 1/3 MnO 3 (LSMO) bottom electrode and different top electrodes [Pt, Ba 0.95 La 0.05 SnO 3 (BLSO)], to determine their photoresponse. The measured short-circuit photocurrent first increases with LFO thickness and then decreases, and it is larger or smaller, when Pt or BLSO electrodes are used, respectively. The corresponding open-circuit voltage displays the opposite trend, being smaller or larger for Pt and BLSO, respectively, which is in excellent agreement with the electronic band alignments determined by x-ray photoelectron spectroscopy and also consistent with the rectifying character of the dark current-voltage data. It turns out that the films display a complex microstructure containing different variants, strained and relaxed, of the orthorhombic LaFeO 3 , that evolves with film thickness and entails the presence of strain gradients and, possibly, flexoelectric fields. We discuss these data and propose that the unavoidable grain boundaries between differently textured LaFeO 3 crystallites play a significant role on the observed responsivity (2.6 × 10 −4 A W −1 ), found to be larger than in related LFO-based structures.

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Section: Lsmo/lfo/blsosupporting

confidence: 88%

Band Alignment and Photoresponse of LaFeO3 -Based Heterojunctions

et al. 2023

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Employing high-temperature-grown SrZrO3 buffer to enhance the electron mobility in La:BaSnO3-based heterostructures

Ngabonziza

Park

Sigle

et al. 2023

Applied Physics Letters

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We report a synthetic route to achieve high electron mobility at room temperature in epitaxial La:BaSnO3/SrZrO3 heterostructures prepared on several oxide substrates. Room-temperature mobilities of 157, 145, and 143 cm2 V−1 s−1 are achieved for heterostructures grown on DyScO3 (110), MgO (001), and TbScO3 (110) crystalline substrates, respectively. This is realized by first employing pulsed laser deposition to grow at very high temperature the SrZrO3 buffer layer to reduce dislocation density in the active layer, then followed by the epitaxial growth of an overlaying La:BaSnO3 active layer by molecular-beam epitaxy. Structural properties of these heterostructures are investigated, and the extracted upper limit of threading dislocations is well below 1.0×1010 cm−2 for buffered films on DyScO3, MgO, and TbScO3 substrates. The present results provide a promising route toward achieving high mobility in buffered La:BaSnO3 films prepared on most, if not all, oxide substrates with large compressive or tensile lattice mismatches to the film.

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Description of electron mobilities in epitaxial lanthanum-doped barium stannate films: Influences of LO phonons, threading dislocation, and ionized donor defects

Thongnum

2023

Journal of Applied Physics

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Lanthanum-doped barium stannate (La-doped BaSnO3 or LBSO) has attracted the attention of researchers and engineers because of its wide range of potential applications in electronic and optoelectronic devices. This is due to a combination of its exceptional room temperature (RT) mobility of 320 cm2 V−1 s−1 and high visible range transparency. However, epitaxial LBSO films made using strategic deposition techniques such as molecular beam epitaxy, pulsed laser deposition, and magnetron sputtering show comparatively low RT mobilities, between 24 and 183 cm2 V−1 s−1, and an accurate description of these RT mobilities is still sought. Herein, we provide the underlying scattering mechanisms related to longitudinal optical (LO) phonons, threading dislocation, and ionized donor defects to elucidate the RT mobilities in LBSO epitaxial films. It was found that the total mobility estimated using Matthiessen's rule provided strong quantitative agreement with experimental results. The large polaron mobility based on LO phonon scattering dominated the whole spectrum of electron concentrations in this system. It was an upper bound mobility, i.e., the mobility limit attained at 320 cm2 V−1 s−1. The calculated mobility associated with LO phonon and threading dislocation scatterings adequately verified the experimental results between 150 and 183 cm2 V−1 s−1. The predicted results for all three scattering types were predominant in experimental data at less than 150 cm2 V−1 s−1. These investigations deepen our understanding of mechanisms governing the charge transport scattering in epitaxial LBSO films and pave the way for the development of novel semiconductor thin films for use in electronic and optoelectronic devices.

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Combined spectroscopy and electrical characterization of La:BaSnO3 thin films and heterostructures

Cited by 4 publications

References 84 publications

Band Alignment and Photoresponse of LaFeO3 -Based Heterojunctions

Band Alignment and Photoresponse of LaFeO3 -Based Heterojunctions

Employing high-temperature-grown SrZrO3 buffer to enhance the electron mobility in La:BaSnO3-based heterostructures

Description of electron mobilities in epitaxial lanthanum-doped barium stannate films: Influences of LO phonons, threading dislocation, and ionized donor defects

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