Mile Ivanda (51) is a Senior Scientist at Ruđer Bošković Institute. He was invited speakeron 13 international conferences. He gave a plenary lecture at the European Conference on Molecular Spectroscopy (EUCMOS) in 2008 year. He published 160 papers (cited 1250 times; H-index 20), among 130 are international refereed of which 81 are in WoS journals.

The research topics:

The research is focused on nanostructural silicon thin films for advanced applications. The Low Pressure Chemical Vapor Deposition (LPCVD) and Physical Vapor Deposition (PVD) were implemented and developed at Ivanda’s group. The different type of silicon based thin films are preparing like silicon reach oxide, silicon reach nitride, amorphous silicon, polycrystalline silicon, doping with boron, phosphorus, erbium and europium; porous silcon by electrochemical etching. The structural, optical, electrical and transport properties are investigating with a goal of development of doped silicon nanostructured films (dots, wires, porous structure) for thermo-electric elements (Peltier cooler and heater, low temperature sensor silicon nanocrystals thin films doped with rare earths for photonics (spherical microresonators, optical amplifiers, lasers),) and porous silicon for biological and chemical sensing. Beside, different aspects of Raman scattering as a powerfull analytic tool has been developed.

Functionalized silicon nanostructures as novel thermoelectric material

The problem of energy in the world has provoked an increased interest, especially after Kyoto’s Protocol, on exploitation of renewable and waste energy. Thermoelectric (TE) devices are able to convert the waste heat form combustion engines, solar energy or from radioactive sources into electrical or some other kind of energy on a pure and non pollutant way. Silicon, the basic material of semiconductor electronics, is widely available, comparatively cheap, ecologically friendly and technologically well developed. Those are reasons enough to seek a marriage between silicon and thermoelectric properties. Recently, Ivanda’s group has found a large Seebeck coefficient of 200 uV/K (the main physical property of TE materials), in a heavily boron doped polysilicon sample obtained by the LPCVD method. By using the LPCVD method, they are producing various kinds of doped silicon nanostructures (dots and wires) in order to obtain those with good TE properties. They also search for advanced TE properties on nanoporous silicon.

Novel silicon based materials for optoelectronics

The research include the production and the characterization of novel silicon based materials for optoelectronics, namely silicon rich oxides (nitrides), silicon oxide /silicon rich oxide (nitride) multilayers, nanocrystalline silicon and europium doped silicon nanocrystalls in silica layers. All of these new materials will be studied in combination with silica microspheres. These thin films on silica microspheres will be investigated in order to examine different non-linear properties under the high laser light intensity excitation conditions. The Stimulated Raman Scattering and optical amplification being the most promising for the construction of silicon-based laser will be searched on this silicon based thin films deposited on silica microspheres. The project includes cooperation between the IFN-CNR in Trentoand the Ruđer Bošković Institute in Zagrebunder the 150.000 euros value research project.

Porous silicon prepared from Silicon On Insulator

Silicon Epitaxy and Poly-Silicon layers. Silicon, an indirect gap semiconductor, can emit light with 10% efficiency at room temperature, provided that it is in the form of low-dimensional (quantum dots or wires) nanostructures. Ivanda's group is producing porous silicon from three types of silicon layers: Silicon On Insulator (SOI), Silicon Epitaxy and Poly-Silicon layers. The structures with novel morphologies that exhibit strong photoluminescence were discovered. The luminescence mechanisms and the relationship between bandgap energy, luminescence energy, and size of nanostructures are investigating. The objectives of such research are:

- to introduce new preparation techniques of visible light emitting Si- materials and to select the most promising among the low-cost technological routes,

- to predict for these materials whether an efficient photo and electroluminescence is feasible and its potential for device application,

- to develop the technologies for porous silicon surface modification in order to ensure its biocompatibility.

Development of new methods and techniques of Raman scattering

The group has significant contribution in development of Raman scattering technique in determination of size distribution of free nanoparticles, of the nanoparticles in matrices and more generally of the size distribution of various nanocomposite materials.  Besides, the portable Raman spectrometer is developing for versatile application in environmental, medicine and food analysis