Periodic Reporting for period 1 - CIGNUS (CuInGaSe Nanowires Under the Sun)
Période du rapport: 2019-11-04 au 2021-11-03
The United Nations 2030 agenda is a wake-up call for everyone to remind us that, while humanity made remarkable progress in a short time, there are still many issues that we must resolve. Climate change is a devastating curse on our civilization: access to affordable and sustainable energy is a decisive step to combat global warming, and, together with improved and innovative infrastructure can help stop its ravaging effects.
Sustainable energy conversion is thus an essential challenge for the future of humanity, as a global shift from fossil fuels to renewable energy is underway as a result of striking climate change concerns. Photovoltaics and battery technologies are at the core of solutions for this issue, and the effort for increased performance, sustainability and affordability is currently at its peak.
Nanowires enable novel paths for this unprecedented situation by reducing necessary resources and pioneering novel science and unique phenomena. In this project, we plan to exploit their properties to save material and improve photovoltaic efficiency by using Se-based materials, which have been proven to have excellent performance in polycrystalline thin films.
Three key project objectives can be identified: the investigation of the growth mechanism and control of the deposition of the nanowires; the study of their optical, electronic, and structural properties; and the fabrication of devices based on them. These challenges were engaged within three main tasks, which are closely interconnected by a continuous feedback of design, fabrication and characterization to constantly improve material quality and application potential.
Sustainable energy conversion is thus an essential challenge for the future of humanity, as a global shift from fossil fuels to renewable energy is underway as a result of striking climate change concerns. Photovoltaics and battery technologies are at the core of solutions for this issue, and the effort for increased performance, sustainability and affordability is currently at its peak.
Nanowires enable novel paths for this unprecedented situation by reducing necessary resources and pioneering novel science and unique phenomena. In this project, we plan to exploit their properties to save material and improve photovoltaic efficiency by using Se-based materials, which have been proven to have excellent performance in polycrystalline thin films.
Three key project objectives can be identified: the investigation of the growth mechanism and control of the deposition of the nanowires; the study of their optical, electronic, and structural properties; and the fabrication of devices based on them. These challenges were engaged within three main tasks, which are closely interconnected by a continuous feedback of design, fabrication and characterization to constantly improve material quality and application potential.
Work was conducted in 6 work packages, 3 focused on technical work and 3 on communication and project management.
In WP1, the fellow developed the substrate fabrication and the growth of CuInSe isolated nanostructures and regular holed material. During the fellowship, CuBiSe thin film materials were investigated as well. In WP2, the fellow characterized in depth the material deposited using several different techniques (among which Raman spectroscopy, XRD, and electron microscopy). WP3 was focused on developing devices based on the isolated nanostructures.
After the first 3 months during which the fellow was trained in the cleanroom and in the details of Molecular Beam Epitaxy (MBE), he focused on developing data analysis programming during the first COVID lockdown. Once experimental work was allowed again, he used a magnetron sputtering system to deposit material to test the substrates fabricated in the cleanoom. After 9 months from the start of the project, the MBE machine was available again for use once the fellow assisted other colleagues during maintenance on the system. Several growth conditions were tested, and it was quickly realized that a high substrate temperature was crucial for selective area growth. Using different substrates with different growth masks and designs, isolated CuInSe nanostructures with precise position control were demonstrated on aluminium oxide islands.
Within WP4, the results from the project are planned to be published in 2 journal publications, one focused on the growth analysis of the deposition of CuInSe nanostructures and their characterization, and one on the material developed based on CuBiSe thin films. Furthermore, the fellow presented his work at 3 international conferences (E-MRS, ACCGE, ICMBE) and several workshops and meetings, such as EuroNanoForum and INL Symposia.
In the framework of WP5, the fellow participated in several outreach activities, including participation in the online 2021 Science is Wonderful event and the International Day of Light.
WP6 was focused on project management, where the fellow learned how to take care of the resources available during the project and to organize funding.
In WP1, the fellow developed the substrate fabrication and the growth of CuInSe isolated nanostructures and regular holed material. During the fellowship, CuBiSe thin film materials were investigated as well. In WP2, the fellow characterized in depth the material deposited using several different techniques (among which Raman spectroscopy, XRD, and electron microscopy). WP3 was focused on developing devices based on the isolated nanostructures.
After the first 3 months during which the fellow was trained in the cleanroom and in the details of Molecular Beam Epitaxy (MBE), he focused on developing data analysis programming during the first COVID lockdown. Once experimental work was allowed again, he used a magnetron sputtering system to deposit material to test the substrates fabricated in the cleanoom. After 9 months from the start of the project, the MBE machine was available again for use once the fellow assisted other colleagues during maintenance on the system. Several growth conditions were tested, and it was quickly realized that a high substrate temperature was crucial for selective area growth. Using different substrates with different growth masks and designs, isolated CuInSe nanostructures with precise position control were demonstrated on aluminium oxide islands.
Within WP4, the results from the project are planned to be published in 2 journal publications, one focused on the growth analysis of the deposition of CuInSe nanostructures and their characterization, and one on the material developed based on CuBiSe thin films. Furthermore, the fellow presented his work at 3 international conferences (E-MRS, ACCGE, ICMBE) and several workshops and meetings, such as EuroNanoForum and INL Symposia.
In the framework of WP5, the fellow participated in several outreach activities, including participation in the online 2021 Science is Wonderful event and the International Day of Light.
WP6 was focused on project management, where the fellow learned how to take care of the resources available during the project and to organize funding.
In the project, the fellow demonstrated the first isolated and position-controlled CuInSe nanostructures, using MBE growth at high temperature. These nanostructure are highly promising as they allow passivation of individual grains and improvement of optoelectronic performance, and can be combined with innovative materials such as perovskites and 2D layers. Further work must be performed to fabricate devices based on the grown material and to understand in detail the properties of the nanostructures. Additionally, preliminary photonic experiments showed that the structures can strongly enhance light-matter interaction and introduce novel phenomena not observed before in this material system, leading to meta-material behavior unheard of before. Finally, the development of the first MBE-grown CuBiSe thin films has boundless untapped potential as the material has not been investigated previously and is expected to have excellent optoelectronics performance.