Higher Conductivity and Enhanced Optoelectronic Properties of Chemically Grown Nd-Doped CaSnO₃ Perovskite Oxide Thin Films

Abstract

Stannous-based perovskite oxide materials are regarded as an important class of transparent conductive oxides for various fields of application. Enhancing the properties of such materials and facilitating the synthesis process are considered major challenging aspects for proper device applications. In the present paper, a comprehensive and detailed study of the properties of spray-coated CaSnO3 thin films onto the Si(100) substrate is reported. In addition, the substrate effect and the incorporation of rare-earth Nd3+ on engineering the characteristics of CaSnO3 thin films annealed at 800 °C are included. X-ray diffraction (XRD) analysis results revealed the orthorhombic structure of all the samples with an expansion of lattice spacing as the substitution of Nd at the Ca site increased. The Raman and FT-IR analysis further confirmed the structural results collected via the XRD analysis. Surface scanning using field-emission scanning electron microscopy revealed the formation of quasi-orthorhombic CaSnO3 grains with an increase in size as dopant content increased. Energy-dispersive X-ray analysis allowed quantification of the elements, while atomic mapping permitted visualizing their distribution along the surfaces. UV–visible spectroscopy and first-principles calculations using density functional theory (DFT) were conducted, and a thorough investigation of the optical and electronic properties of the pure material upon Nd3+ insertion was provided. Electrical properties collected at room temperature revealed a growing conductivity upon doping ratio increase with a simultaneous enhancement in the carrier concentrations and mobility. The findings of the present work will help facilitate the synthesis procedure of large-area stannous-based perovskite oxide thin films through simple and efficient chemical solution methods for optoelectronic device applications.

Optical investigation and computational modelling of BaTiO3 for optoelectronic devices applications

“…Attempts were introduced in the literature to modulate the band gap, seeking visible absorption 23,24 . However, the wide band-gap BaTiO 3 is still very beneficial as a UV absorber 26,27 , especially in perovskite solar cells 28,29 , as reported in 20 . Another work utilized BaTiO 3 in perovskite thin films but with Si-doping 25 and other dopants 30 .…”

Tuning the catalytic performance of CaSnO3 by developing an S-scheme p–n heterojunction through Ag6Si2O7 doping

“…48) and the n-type CaSnO 3 (ref. 57) touch one another. For the alignment of energy band levels of Ag 6 Si 2 O 7 and CaSnO 3 at the same level, this heterojunction creates an electric field at the interfaces of these two different nanostructures.…”

Doping the Undopable: Hybrid Molecular Beam Epitaxy Growth, n-Type Doping, and Field-Effect Transistor Using CaSnO3

“…Shaili et al have arguably achieved Nd doping in polycrystalline CaSnO 3 films, but the room-temperature mobility remained <4 cm 2 V −1 s −1 . 22 Here, by growing CaSnO 3 on GdScO 3 (110) substrates within an adsorption-controlled growth window using hybrid molecular beam epitaxy, we show that CaSnO 3 not only can be doped but can achieve robust and predictable doping that spans a 5-fold range of carrier concentrations. It is noted that despite having ideally lattice-matched DyScO 3 (110) substrates, GdScO 3 substrates were chosen due to their low lattice mismatch and tilt mismatch (Figure 1b) because it allows for the unambiguous determination of the out-of-plane lattice parameter of films owing to distinct peaks from the film and the substrate.…”

“…Perhaps this result was unsurprising given that Weston et al had already warned that “doping [CaSnO 3 ] looks particularly challenging” from their theoretical studies. Shaili et al have arguably achieved Nd doping in polycrystalline CaSnO 3 films, but the room-temperature mobility remained <4 cm 2 V –1 s –1 …”