The Regional Conference of Solid State Science and Technology (RCSSST) is an annual event in Malaysia. This 25th Conference 2009 is jointly organized by the School of Microelectronic Engineering and Institute of Nanoelectronic Engineering (INEE), Universiti Malaysia Perlis as the host, in cooperation with Malaysian Solid State Science & Technology Society (MASS). The aim of this conference is to provide a platform for discussions of Solid State Science and Technology in all aspects of physical and chemical properties, preparation and characterization techniques, optical properties; macro-; micro- and nano-structures. In addition, modeling, simulation, measurement methods as well as current developments in technology will also be discussed.