Prof. Dr. Vadim Sirkeli

Age: 38

Area of research: III-VI and II-VI Semiconductor materials; Light-emitting devices with cadmium-free quantum dot emitters; Terahertz Quantum Cascade Lasers

Name of my Research Institute: Comrat State University, Department of Information Technologies, Mathematics and Physics, Comrat, Moldavia

Research period at the TU Darmstadt: September 2016 to February 2018

Prof. Dr. Vadim Sirkeli. Photo: Claus Völker

Questionnaire to the Research Fellow

My field of research is fascinating. To laymen I would explain it in the following comprehensible manner:

Colloidal quantum dots (QDs) are solution-processes nanoscale crystals of semiconductor material. The unique size-dependent optoelectronical properties and high emission quantum yields of quantum dots have motivated increasingly active research on their application in the next generation optoelectronic devices, including applications in full-color flat-panel displays or as low power consumption solid-state lighting sources. Most high brightness and efficiency quantum dot light-emitting devices (QD-LEDs) currently fabricated are based on cadmium-containing quantum dots (CdSe, CdS, CdTe, CdSSe, etc.), which are of environmental and cost concern. In this project we will examine new design and architecture of solution-processed all-inorganic QD-LEDs with cadmium-free quantum dot emitters. Also new concept and structure of Terahertz Quantum Cascade Lasers based on II-VI materials will be investigated.

My most important success in research to date is

the development and the numerical investigation of GaN/ZnO-based light-emitting diodes (LEDs) with new device structure employing the p-NiO and n-ZnSe interlayers. It is established that the insertion of both p-NiO and n-ZnSe interlayers leads to the enhancement of charge carrier-confinement in the active region and to the significant increase of internal quantum efficiency (IQE) of the LED device up to 82%, which is comparable with IQE values in order to obtain better AlGaN- and InGaN-based LEDs.

Prof. Dr. Vadim Sirkeli with his host Professors em. Dr. Eng. Dr. h.c. mult. Hans L. Hartnagel and Dr.-Ing. Franko Küppers. Photo: Claus Völker

I’ve chosen the TU Darmstadt because…

it is an excellent university with an international reputation, which has very strong competences in the engineering science and research. Research groups led by my hosts Professor Hans L. Hartnagel and Professor Franko Küppers are very renowned worldwide and make strong progress in the area of material science, fabrication and characterization of the devices for photonic and THz applications.

Questionnaire for the host

Guest of: Prof. em. Dr. Eng. Dr. h.c. mult. Hans L. Hartnagel and Prof. Dr.-Ing. Franko Küppers

You appreciate in your guest: Professor Sirkeli is not a first-time visitor here at our Institute at TU Darmstadt. He’s been here for shorter visits before and we were always impressed by his ideas, by his contributions to our projects, and by the research he’s conducting back home at his own group at Comrad Staat University. Vadim always integrated himself very fast into our team and made significant contribution even when his visits were short and all team members like(d) to work with him.

Prof. em. Dr. Eng. Dr. h.c. mult. Hans L. Hartnagel. Photo: Claus Völker

Department: Institute for Microwave Engineering and Photonics

You, your team and the TU Darmstadt benefit from your guest’s…

Professor Sirkeli’s work, expertise, and experience ideally matches in a complimentary manor with our work in electronic semiconductors, Terahertz sources, and advanced light emitting devices. We already benefitted from collaborating with him in the past as can be seen by joint publications in renowned international scientific journals.

Prof. Dr.-Ing. Franko Küppers. Photo: Claus Völker