1.      The studies of photoelectrical and optical properties of amorphous and nanocrystalline thin-film semiconductors using the Steady-State Photocarrier Grating (SSPG) technique and sepectrophotometry. The transport parameter (diffusion length) and the mobility-lifetime product of minority carriers can be determined from theoretical analysis based on the solutions of transport equations for photoelectrons and photoholes using different methods. Moreover, the optical constants can be extracted from theoretical analysis based on Swanepoel model. Currently, analytical treatments are used to solve the continuity equations for photoelectrons and photoholes in order to obtain more accurate solutions and the results can be compared with those of other methods. The new adopted methods may allow for better values of transport parameters and provide further information about transport properties. Simplified versions of the continuity equations can also be solved and the solutions may have significant importance from the physical point of view.

2.      The study of electrical properties of compound nanostructures (like ZnO nanowires, nanorods and nanosheets) fabricated as heterojunction devices, is another interest. In this analysis, a Gaussian distribution of low barrier heights was considered and effective barrier heights were extracted for a wide range of temperatures. Then mean barrier height of the heterojunction device was determined. FORTRAN program was developed using Tung model to analyze the temperature-dependent current-voltage characteristics. Four free parameters (which have physical importance) are critically varied to get the best fit to the experimental data and the best fit is judged using c² indicator.