ELFT HÍRADÓ

[Szeminárium koordinátor <sem-admin AT szfki.hu>]

Habilitation lectureBeke DávidHUN-REN Wigner RCP SZFINanostructured Photon 
Emitters: From Silicon Carbide Nanoparticles to Tunable Spinel 
ScintillatorsTuesday, 29 October 2024, 10:00, KFKI Campus, Bldg. 1, 2nd 
floor, Conference RoomIn this seminar, I present the culmination of my 13 
years of research at the Wigner Research Centre for Physics, with a focus on 
the last 9 years following my PhD, along with my future research plans. Under 
the supervision of Adam Gali and with the support of numerous researchers 
within the institute, I have investigated the synthesis and optical 
properties of silicon carbide (SiC) nanostructures, with the aim of 
understanding their emission characteristics and shifting the emission 
towards the red and infrared regions for potential applications.These SiC 
nanostructures, particularly ultrasmall nanoparticles, are predominantly 
fabricated through stain etching, which involves HF and HNO3 at elevated 
temperatures. While SiC exists in over 250 polytypes, only cubic SiC can be 
etched using this method. Our research into the reaction mechanism has led us 
to describe a process that reveals simultaneous electron and hole injection, 
which accounts for the observed polytype selectivity. We have termed this 
process "No-Photon Exciton Generation Chemistry – NPEGEC" for SiC etching. 
This understanding enabled us to control nanoparticle size and describe their 
optical properties as a function of size and surface characteristics. Despite 
this control, even the largest SiC nanoparticles emit green to yellow light 
due to their intrinsic band gap.As our research progressed, we shifted focus 
towards quantum emitters in solid-state systems. Color centers, typically 
point defects within a crystal structure, enable sub-bandgap emission with 
additional features. In my presentation, I will demonstrate the purely 
chemical synthesis of silicon vacancies and divacancies in SiC particles, 
including nanoparticles, without the involvement of high-energy particle 
interactions, a rare and significant achievement in the field.Finally, I will 
introduce my current research enthusiasm: spinel scintillator nanostructures, 
whose optical properties can be tuned across the emission wavelength and 
decay time. I am confident that these materials not only offer exciting 
prospects for fundamental research but also hold immediate potential for 
real-world applications.  Minden érdeklődőt szívesen látunk! - Everyone 
is welcome to attend.Attila Nagysem-admin AT szfki.hu