Karl Jonas Riisnaes, The 1966 PhD Scholar
Postgraduate Researcher, EPSRC Centre for Doctoral Training in Metamaterials (XM2)
I am writing to give an update on my research which is kindly supported by the 1966 PhD scholarship. I started my research into metamaterials at the University of Exeter in September 2018. I am now well into my PhD, approaching my 4th and last year which I will commence in September 2021. Recently much of my research has been focused on establishing methods for measuring the perovskite crystal devices I am developing and have obtained some very encouraging results comparable and surpassing the state of the art.
Project overview
- Establish and investigate the viability of transportation and storage of Organo-Halide Perovskite Crystals from our collaborators in Italy to our facilities in Exeter.
- Examine methods of device fabrication based on Organo-Halide Perovskite Crystals.
- Crystal exfoliation and transfer to Silicon substrates to obtain few layer crystals for device manufacturing.
- Electrical contact deposition on crystal though orthogonal electron beam lithography.
- Fabrication and measurement of perovskite based photo transistor.
- Fabrication of perovskite based light emitting diode.
- Achieve electrically induced lasing by demonstrating an electrically driven hybrid graphene and perovskite laser.
Research progress to date
As mentioned in previous updates I have found an effective way of using electron beam lithography based methods to deposit metal electrodes on the perovskite crystals we are researching. This is a novel method within the field and enable nanometer scale devices to be fabricated with simple steps as shown in the diagram below. This method improves the resolution a thousand fold compared to conventional processing methods for the perovskite crystals. Optoelectronic measurements on devices fabricated with the method shows key parameters comparable and surpassing the state of the art and we are currently writing a paper aimed at a high impact journal with our results. I am currently working on a method to produce lateral LED structures with the perovskite crystals which I believe would be ground breaking in the field.
Practical experience gained
Through the characterisation of the produced devices I have learned a lot about how to take very sensitive measurements and use optical and electrical equipment at the very limits of what it is capable of. Due to various difficulties with the measurements I have also had to design and assemble various electrical circuits and troubleshoot and fix broken circuitry. All of this has really enhanced my understanding of both the physics and the metrology.
Thank you
Again, I would like to specify my appreciation and gratitude for the support this scholarship provides in my day to day research. Financially it really helps me focus without the worry or distraction of needing to undertake additional paid work, ensuring I can deliver my research to the highest standard.
I very much look forward to keeping you updated on my progress.