In the last several years, thin-film structures of amorphous silicon and other semiconductor materials have become an important segment of optoelectronics and macro electronics, especially in the fields of photovoltaics, sensorics and the fast developing flat-panel displays. Main advantages of thin-film structures are the rational usage of the limited natural reserves of semiconductor (and other) materials, possibility of deposition of thin layers over large areas using low temperature processes, which contributes to the reduction of the energy consumption in the production of semiconductor structures. Plasma enhanced chemical vapour deposition (PECVD) is a low temperature production technology that enables deposition of homogeneous thin amorphous silicon films on various types of substrates - besides glass and monocrystalline silicon, there is also an option of using flexible metal or plastic large area substrates. The possibility of deposition of thin amorphous silicon films on the pre-processed silicon wafers enables production of hybrid optoelectronic sensors and systems that combine advantages of high optical sensitivity of amorphous silicon structures with efficient immediate signal processing capabilities of high performance integrated circuits produced in standard technology. Thin-film optoelectronic structures of hydrogenised amorphous silicon (a-Si:H) represent a specific electrical and optical system, where due to the small layer thickness and special structural designs different electrical and optical effects, like charge carrier tunnelling through thin potential barriers and coherent light propagation in thin-layer systems for example, are more pronounced. Computer based modelling of electrical and optical phenomena occurring in specific a-Si:H structures and their influence on external device characteristics is very important for successful analysis and optimisation of those structures. In photovoltaics, optical modelling of light scattering phenomena in solar cell structures with rough interfaces currently presents one of the most interesting challenges. Analysis and optimisation of light scattering on rough interfaces can greatly improve optoelectronic properties and increase efficiencies of thin-film solar cell and other similar structures. Our research group has proven to be at the same scientific level as the prominent European and other internationally acknowledged research groups working in the field of thin-film structures of amorphous silicon and other semiconductor materials, which is reflected in the numerous European and world-wide bilateral co-operations and projects. Group members are demonstrating their investigation results and achievements on recognised international and Slovenian specialised conferences. The contribution to the international scientific sphere and knowledge is accomplished with publications in internationally acknowledged reviews and magazines.