Student Seminar Session: Applied Physics (1/2)

martes 12 mar. 2024 15:00 → 17:30 Europe/Madrid

Semisotano parque científico, sala SS6, bajo el IFIC

15:00 – 15:30 Mahesh eledath changarath

Title: 2D materials for optoelectronic applications

The discovery of graphene sparked a broad interest in research on two-dimensional (2D) layered materials. The relentless pursuit of semiconductor materials capable of delivering enhanced optoelectronic performance has led researchers to explore novel avenues in the realm of two-dimensional (2D) materials. Layered semiconductors belonging to the Group III-VI family, such as gallium selenide (GaSe), indium selenide (InSe), and gallium telluride (GaTe), exhibit intriguing properties owing to their atomically thin structures. These materials manifest a diverse range of electronic band structures, allowing for tailoring their optoelectronic behaviour and fostering versatility in device design. In this seminar, we discuss the general properties of 2D materials and then we focus on an interesting application of InSe, which is a member of Group III-VI family.

15:30 - 16:00 Alejandro Martínez Serra

Tittle: First approach to discover new perovskites for solar cells by engineering its composition with AI

Hybrid organic-inorganic halide perovskites  have emerged to be an interesting materials due to their good photovoltaic properties such as high charge carrier mobility, broad and strong optical absorption, long free carrier diffusion length and low exciton binding energy which makes them prominent candidates for solar cell applications rivalling conventional silicon cells as they have advantages over them such as being more cost-effective and have an easy solution process manufacture, also recent studies have achieved better power conversion efficiency (PCE) values. However, as their stability remains an issue, this work proposes the use of Artificial Intelligence to find new candidates with better stability to overcome the aforementioned issue.

Coffe Break

16:15 – 16:45 Jesús Ortiga -Fibla

Tittle: Ultraviolet light assisted Kelvin probe force microscopy for the study of dislocations in GaN structures for power devices

The combination of the outstanding properties of GaN with vertical architectures is expected to open the door to a new generation of power devices. However, its growth on foreign substrates, necessary for a reduction in production costs, still results in high dislocation densities (~109-10 cm-2) that may have a detrimental effect on device performance. A deeper understanding of the role of surface and dislocation’s charge dynamics is hence necessary for the improvement of device reliability. Our work uses ultraviolet (UV) above band-gap light assisted Kelvin probe force microscopy to characterize electrical properties of GaN dislocations.

16:45 – 17:15 Parmenio Boronat Sevilla

Tittle: Dynamic evolution of surface states under illumination in single crystal perovskites

In this work, we study the time evolution of optoelectronic processes in bulk SC MAPbBr3 perovskites. These processes are sensitive to light, and to measure them, we have analyzed the SPV response of the perovskite to several power sources and time exposures. The main techniques to do so are Atomic Force Microscopy (AFM) and Light-assisted Kelvin probe force microscopy (KPFM) has been used to obtain the topography and surface potencial at nanoscale, respectively. In addition, the SPV transient data has been fitted into a single state model in both light and dark evolution. This method grants a quantified viewpoint to our results, as diode-like behaviour, time relaxation and irreversibility have been estimated under all prepared conditions and surfaces have been classified and distinguished according to these values.