Thermal Laser Epitaxy for Ultraclean Heterostructures

We have developed a new thin-film deposition technique that is especially suited to the growth of an extremely wide range of heterostructures with atomic precision. Thermal laser epitaxy (TLE) employs continuous wave lasers to simultaneously heat both substrates and freestanding elemental sources [1]. The lasers’ virtually arbitrary power density allows for the evaporation of practically all elements of the periodic table in the same setup while maintaining process gas environments up to pressures as high as 10^-1 mbar [2]. For substrates heated directly via CO₂ laser, temperatures up to and beyond 2000 °C can be reliably reached on virtually all commercially available oxide substrates, unlocking previously inaccessible growth regimes in many materials systems. In combination, these advantages suggest the potential of TLE to greatly expand thermodynamic parameter space for ultraclean epitaxial thin film synthesis. Here, I will introduce and discuss the advantages of TLE for epitaxy and present a wide range of recent results demonstrating the epitaxy of ultraclean thin film heterostructures using the technique [3,4].

[1] W. Braun, J. Mannhart, AIP Adv. 9 (2019) 085310
[2] T.J. Smart, et al., J. Laser Appl. 33 (2021) 022008
[3] D.-Y. Kim, J. Mannhart, W. Braun, Appl. Phys. Lett. Mater. 9 (2021) 081105
[4] D.-Y. Kim, J. Mannhart, W. Braun, J. Vac. Sci. Tech. A 39 (2021) 053406