Perovskite oxides are ABO3‐type compounds with a crystal structure capable of accommodating a large number of elements at A‐ and B‐sites. Owing to their flexible structure and complex chemistry, they exhibit a wide range of functionalities as well as novel ground states at the interface. However, in comparison with conventional semiconductors such as silicon, they possess orders of magnitude lower room‐temperature electron mobilities limiting their room‐temperature electronic applications. For example, in a prototypical doped SrTiO3, the room‐temperature electron mobility remains below 10 cm2V−1s−1regardless of the defect minimization. Discovery of high room‐temperature mobility in alkaline‐earth stannates such as BaSnO3and SrSnO3constitutes a significant advancement toward all‐perovskite electronic and spintronic devices. Alkaline‐earth stannates also possess wide‐to‐ultra wide bandgaps that make them potentially suitable candidate for transparent conductors, power electronic devices, and high electron mobility transistors. This article provides an overview of the recent progress made to these materials' electrical properties with particular emphasis on the advancements in the molecular beam epitaxy approaches for their synthesis, and defect control.
The prospect of 2‐dimensional electron gases (2DEGs) possessing high mobility at room temperature in wide‐bandgap perovskite stannates is enticing for oxide electronics, particularly to realize transparent and high‐electron mobility transistors. Nonetheless only a small number of studies to date report 2DEGs in BaSnO3‐based heterostructures. Here, 2DEG formation at the LaScO3/BaSnO3(LSO/BSO) interface with a room‐temperature mobility of 60 cm2 V−1 s−1at a carrier concentration of 1.7 × 1013 cm–2is reported. This is an order of magnitude higher mobility at room temperature than achieved in SrTiO3‐based 2DEGs. This is achieved by combining a thick BSO buffer layer with an ex situ high‐temperature treatment, which not only reduces the dislocation density but also produces a SnO2‐terminated atomically flat surface, followed by the growth of an overlying BSO/LSO interface. Using weak beam dark‐field transmission electron microscopy imaging and in‐line electron holography technique, a reduction of the threading dislocation density is revealed, and direct evidence for the spatial confinement of a 2DEG at the BSO/LSO interface is provided. This work opens a new pathway to explore the exciting physics of stannate‐based 2DEGs at application‐relevant temperatures for oxide nanoelectronics.
more » « less- Award ID(s):
- 2039380
- NSF-PAR ID:
- 10366624
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Science
- Volume:
- 9
- Issue:
- 12
- ISSN:
- 2198-3844
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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