on the holding of Symposium K
“ZnO Material Science from researches to electronic applications”
EMRS Fall Meeting, September 16-20, Warsaw, Poland.
ZnO is a well-known wide-gap semiconductor, that has a combination of unique properties, such as almost complete analogue of GaN with 3 times more larger exciton binding energy, providing more effective light emitting at room temperature, and world of outstandingly various nanostructures for different applications in nanoelectronics. Increasing amount of publications (which exceed those ones for GaN and SiC), numerous conferences devoted to ZnO are confident evidence for enormous prospectives of this material. Moreover, applications of ZnO are favored by economic and environmental benefits of its usage as wide-gap semiconductor in electronics. Nevertheless, ZnO applications have not corresponded to its wide possibilities yet. The main idea of Symposium K was to narrow the evident gap between the research groundwork on ZnO and its possible industrial introduction.
Symposium K gathered 82 participants from 28 countries including such remote ones as Japan, South Korea, Malaysia and Mexica. 10 invited talks, 25 oral presentations and 42 posters were contributed to the Symposium.
During the Symposium the original initiative, called The Material Research Day was held, where all the Fall Meeting participants were invited. They had a possibility to listen the specific talks of companies, producing state-of-the-art equipment for researches, such as: Oxford Instruments and AP Vacuum. Participants had a possibility to communicate directly to the representatives and to receive the thorough answers concerning the new material research technologies. Catherine Joce (CRM_InnoNet Project) presented the idea of Critical Row Materials Substitution Project connected with a lack of certain chemical elements in Europe, what in some cases results in a 100% import and dependence of European countries from outer suppliers.
As a result of the Symposium it was confirmed that ZnO doped by donor impurities is a reasonable alternative to presently applying In-Sn-O alloys (ITO). Among trace elements gallium and indium play very important role in solar energetics and optoelectronics (light emitting and laser diodes – LEDs and LDs). Indium is the component of ITO transparent electrodes which serve as front contacts for contemporary industrial solar batteries for a large-scale production. Indium world deposits are strongly restricted (1,2∙104 t) and In price grows with a time. Only 100 t of In are deposited in Europe (Ireland). The cost of In is 600 Euro per kg what is 440 times more expensive, than that of Zn ( 1.4 Euro per kg). Moreover, world deposits of zinc are about 4,5∙1012 t. Therefore the substitution of indium with zinc in photovoltaics and optoelectronics is of great importance for European community. Thus, the idea of In substitution in indium tin oxide alloys with ZnO doped by Al in solar energetics is under implementation in Japan under the supervision of Prof. Tetsuya Yamamoto (Kochi University). Furthermore, a fabrication of blue and green light emitting diodes (LED) and lasers on the basis of gallium-indium nitrides requires large consumption of gallium and indium. Thus the substitution GaN to ZnO in LEDs and lasers is of great importance also. For these devices the development of quantum structures on ZnO is necessary. In this activity there are difinite achievements on laboratory scale. The success in obtaining long term p-type ZnO was demonstrated within Symposium K.
Another realized original initiative was Round Table within the Symposium. The nowadays research and development in the field of ZnO films and nanostructures were considered. The vital problems ZnO applications, i.e. p-type conductivity, intrinsic defects and the correlation between researches in the areas of usual and nanostructured ZnO based materials were discussed. The following problems of ZnO such as unclearness with a life-time stability of p-type state at doping by acceptor impurities, self-compensation phenomena, oxygen component of ZnO influencing on chemical state of dopants, necessity for exact holding of technological parameters which strongly influence on properties of grown films, were considered.
The participants of the Symposium agreed that for the first stage solar energetics needs transparent conductive films for a substitution of indium containing material. The researches of ZnO nanostructures are of importance for contemporary and future applications. The participants agreed to collaborate in the Frame Program 8, Horison 2020 and to ask for the supports of European community and European Material Research Society. For this aim it is necessary to announce the call titled as “ZnO based advanced value added photo-voltaic solutions (In less PV)”.
Each scientist working in the area of ZnO has to think about its applications. The latter are motors of the projects and improve financing of fundamental investigations. We have not to forget that promising applications need very deep and strenuous fundamental studies for their comercialization. Therefore one should remember that fundamental science is the basis of applications.
The participants of Symposium K were satisfied by the activity of Organizating Committee members: Prof. Robert Triboulet, Prof. Robert Kudrawiec, Prof. Rositza Yakimova, Prof. George Lashkarev and Dr. Serhiy Trushkin.
At the end of Symposium two young authors of poster presentations and the author of oral talk were awarded by President of EMRS and Principal Organizer of Symposium K. The participants agreed that ZnO Symposiums devoted to applications of this semiconductor should be organized every two years.
The Symposium K organizers are very much grateful to the administration of EMRS HQ and the administration of Warsaw Fall Meeting for attention and everyday help in organizing of Symposium and its leading.
Principal Organizer of Symposium K
Professor George Lashkarev