Adsorption-controlled epitaxy of perovskites

TL;DR

This paper introduces a novel laser heating epitaxy method combining advantages of MBE and PLD to grow complex oxides with high purity and stoichiometry control, enabling new material synthesis regimes.

Contribution

The proposed laser epitaxy technique uniquely allows growth in adsorption-controlled regimes of complex oxides, expanding capabilities beyond traditional MBE and PLD methods.

Findings

Potential to grow SrTiO₃ in adsorption-controlled regime

Enables synthesis of low-impurity heterostructures

Scalable to large substrates for mass production

Abstract

I propose to use laser heating both for the substrate and the thermal evaporation sources in a vacuum chamber operating at pressures from XHV to values where the mean free path of the particles approaches or slightly exceeds the source-substrate distance. The concept combines the advantages of the molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) methods to allow ultrapure deposition with continuous stoichiometry variation at high background pressures of arbitrary gases or molecular beams. Theory and preliminary experiments suggest that this setup is capable of growing complex oxides such as SrTiO$_3$ in the adsorption-controlled regime, similar to GaAs, in a background of molecular oxygen. This regime is neither accessible to MBE nor to PLD, making this laser epitaxy approach a unique tool to explore new growth regimes with the potential to fabricate structures such as modulation-doped heterostructures with low levels of background impurities that are impossible to synthesize with the current techniques. The technological simplicity and exceedingly compact size of the deposition chamber enable easy and rapid switching between different materials systems and the efficient synthesis of new materials that involve corrosive constituents. In contrast to PLD, the method may be scaled in a straightforward manner to large substrate sizes, providing a direct path from research to mass production.