PhD - Leuven | More than two weeks ago
Determining laser parameters to allow a smooth detachment of epitaxially grown III-V layer from their parent substrate
III-V semiconductors have arisen as promising candidate for a myriad of technological developments such as: RF, optoelectronics, or photovoltaics; thanks to their unmatched opto-electronics properties. III-V active layers are usually grown on monocrystalline III-V substrates which are very costly due to the scarcity and the high cost of their elemental compounds. To enable the integration of III-V on Si wafers different approaches are being explored, one of them is the selective detachment of the active layers from the parent substrate which would allow to reuse these substrates and substantially decrease the overall cost and environmental impact of this process .
Different methods have been so far explored with varying degrees of success, the selective wet etching of a sacrificial layer shows promising results but is very lengthy, mechanical detachment based on crack propagation is very fast but difficult to control and is leading to rough surface . Lastly a new approach based on the selective absorption of an infrared (IR) laser energy by a low band gap sacrificial layer that is then ablated has shown interesting preliminary results. Fundamental understanding and optimisation of the process is needed to obtain a scalable and repeatable method .
In this project, the Ph.D candidate will work on the modelization of the absorption of high energy laser pulse in III-V material. After definition of an optimized epitaxial structure laser ablation tests will be performed on the optimized structure. Physical and chemical characterization of the ablated layer will be performed to understand underlying ablation process. The insights from this fundamental research will help to further optimize the ablation method and to obtain a scalable and repeatable detachment process.
  J. S. Ward et al., Progr. in Photovoltaics: Research and Applications, vol. 24, no. 9, pp. 1284–1292, 2016
  W. Choi et al Adv. Energy Mater., vol. 4, no. 16, p. 1400589, 2014
  J. Chen and C. E. Packard, Solar Energy Materials and Solar Cells, vol. 225, 2021
 A. Jan et al. Adv Energy Mater, vol. 20, no. 1, 2018
Required background: Material Sciences, Engineering Science, Nanotechnology
Type of work: 30% modeling/simulation, 50% experimental, 20% literature
Supervisor: Clement Merckling
Daily advisor: Steven Brems, Francois Chancerel
The reference code for this position is 2023-049. Mention this reference code on your application form.