Hans Boschker

Affiliation: Max Planck Institute for Solid State Research, Germany

Date: April 21, 2021; 17:00 – 18:00

Laser-Light for Epitaxy

For the scientific development of quantum-matter heterostructures and for a range of potential applications, the growth of high-purity heterostructures is required. 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)uses chemical elements as sources that are evaporated with continuous-wave lasers [1]. The lasers’ virtually arbitrary power density allows for the evaporation of almost all elements of the periodic table in the same setup. This is demonstrated by showing elemental metal films of a large range of elements; from high-vapor-pressure elements like S and Bi to low-vapor-pressure elements like W and Ta [2]. I will discuss the benefits of thermal laser epitaxy for high-purity deposition of materials and heterostructures with almost all elements from the periodic table. Compared to existing methods such as molecular beam epitaxy and pulsed laser deposition, TLE is clean, simple, fast, and versatile. Furthermore, I will present the results of a new substrate heater that is based on a ~10 µm laser [3]. This laser light is directly absorbed by oxide crystals and therefore allows for a heating system that is ultra-clean, has very fast ramp rates, and can reach extremely high temperatures.

[1] Film Deposition by Thermal LaserEvaporation, W. Braun and J. Mannhart, AIP Advances 9, 085310 (2019).
[2] Thermal Laser Evaporation of elements from Across the Periodic Table, T.J. Smart, et al., J. Laser Appl. 33,022008 (2021).
[3] In situ Thermal Preparation of Oxide Surfaces, W. Braun, et al., Appl. Phys. Lett. Mater. 8, 071112 (2020).