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Petr Vacek recently successfully completed his doctoral studies and started his new research position as a postdoctoral fellow at the University of Cambridge, where he will be part of the electron microscopy research group at the Institute of Materials Science and Metallurgy.
Petr Vacek carried out his doctoral studies in cooperation with the Institute of Physics and Materials (IPM) at the Department of Experimental Studies and Structural Modeling of Structure and CEITEC BUT (study program Advanced Materials and Nanosciences). He completed his doctoral studies under the supervision of Roman Gröger. Peter Vacek's career path that brought him to Cambridge was influenced by the research focus of the Roman Gröger research group and by Roman Gröger´s leadership abilities. Peter received his first research experience at Cambridge thanks to the OP VVV mobility project during his PhD studies. What is so interesting about electron microscopy and why did he join Roman Gröger's research team? How did the CEITEC PhD School prepare him for his scientific career abroad? And how did he remain motivated during his doctoral studies?
Why did you decide to apply for doctoral studies at CEITEC?
I applied for the subject Extended Defects in Ga and Al Nitrides, which was opened by Roger Gröger, the head of the Multiscale Modelling and Measurement of Physical Properties research group at CEITEC of the Institute of Physics and Materials. I was interested in this topic because it involved the study of semiconductor materials with the help of electron microscopy, which are topics that had already interested me during my master's degree.
And what interested you in the field of electron microscopy?
The field of electron microscopy fascinated me because of its complexity and number of applications. For example, you can use scanning electron microscopy to examine the surfaces of materials at a much higher resolution than with light microscopy. With transmission electron microscopy, you can observe the internal structure of the material and at the same time its chemical composition, and with one single method you can determine the composition of the material. Also, the fact that you can look directly at the atomic structure of the material is just the icing on the cake.
Why did you choose to join Roman Gröger's research group?
I liked that Roman Gröger´s research group was combining experimental study of materials with various forms of theoretical modelling and simulation. Some questions from the field of materials science are very difficult to answer with only experimental or only theoretical methods. If the problem can be examined from various points of view and combining theoretical and experimental methods, it often brings new discoveries that would not be otherwise possible to obtain due to the limitations of each of these approaches. I also found it appealing to join such a young research team and the opportunity to collaborate on other topics addressed by the research group.
What did you focus on during your doctoral studies?
I studied the structure of defects in materials based on gallium and aluminium nitrides, which are semiconductor materials that are used to make blue light emitting diodes (LEDs), LED backlit displays, home LED lighting or blue lasers. The properties of semiconductor materials are largely determined by the defects that occur in them. It is therefore necessary to know how a particular type of defect affects the properties of the material, why it arises and whether it can be eliminated in some way or used to achieve the desired properties. As an example, I would mention P or N doping, where atoms with more or less valence electrons than the base material are purposefully introduced into the material. In this way, it is possible to obtain a semiconductor with an excess of holes or electrons, and those can be used as free charge carriers. On the contrary, some defects reduce the efficiency of LEDs or completely prevent their proper functioning, and in such cases, it is necessary to look for ways to get rid of these defects.
What do you consider the most important thing you learned during your PhD?
I would say that the most important thing for me was to gain knowledge in the field of electron microscopy, which ultimately helped me get a postdoctoral position at the University of Cambridge. Brno is one of the world's leading centre of electron microscopy and as such provides excellent conditions for education of students and professional development of researchers in this field.
What did you like most about the CEITEC PhD School and Roman Gröger's group?
What I liked the most was the friendly atmosphere in the group, great freedom in the field of science and open access to top electron microscopes both at CEITEC Nano and at the Institute of Physics of Materials. I also appreciated Roman Gröger's international collaborations, thanks to which I participated in a six-month internship at the University of Cambridge. I also liked the opportunity to attend international conferences, at least until it was interrupted by the COVID19 pandemic.
Is there anything you were afraid of when you applied to the CEITEC PhD School? Did you manage to overcome this fear and how?
I don't think there's anything to worry about. In comparison with the master's study, the doctoral study emphasizes independent work and the acquisition of new knowledge in the given field. One must be a bit curious, think about the topic, look for solutions and not be afraid to fail.
Do you have any tips for other doctoral students? How to stay motivated in demanding doctoral studies?
I guess one needs to see some sense behind everything we do. Whether a PhD study makes sense in our career or, perhaps more importantly, seeing a purpose in the research one does. If it stops making sense at some point during the study, it is very difficult to find motivation to continue.
You are now a postdoctoral fellow at the University of Cambridge in the United Kingdom. Do you feel that the CEITEC PhD School has sufficiently prepared you for this position?
First of all, one has to have the ambition to go abroad, it won't work without it. After that, one only needs a great deal of luck, especially considering the people one meets during his/her career. Very important roles are played by the supervisor and colleagues, but also the people who will be interested in one’s results. Nevertheless, it is also necessary to encounter good fortune halfway, especially through hard work and building through acquiring contacts and networks. And I have to say that there are good conditions to do so at CEITEC and the Institute of Physics and Materials.
What do you enjoy doing in your free time? How do you relax to regain the needed energy to devote yourself fully to science?
I like sports, or I play board or computer games. The most important thing is to find a time when one does not think about work. I would also like to highlight a very underestimated activity in today's hectic time, and that is doing nothing. Sometimes it is very beneficial to turn off and sort out your thoughts completely, at least for a while.
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