Abstract
AbstractThere are a variety of processes for preparation of semiconductor nano-co- mposites, such as chemical vapor deposition (CVD), chemical colloid, reverse micellar, and electrodeposition. Among them, electrochemical techniques provide several advantages, including low temperature processing, arbitrary substra- te shapes, controllable film thickness and morphology, and potential low produ- ction cost. Consequently, preparation of semiconductor nano-composites with the electrochemical technique has become increasingly popular nowadays.In this thesis, semiconductor/polymer nano-composites were prepared with the electrodeposition process. The substrate is a gold film deposited on fre- shly cleaved mica and subjected to prolonged annealing at 250℃ forming an epitaxial, polycrystalline substrate. The polymer matrix is polypyrrole (PPy) and the semiconductor multiple-layer is alternating CdSe and CdTe thin films.The optical properties, surface morphology, composition and composition distribution of the resulting semiconductor/polymer nano-composites were characterized by UV/Vis, PL, AFM, SEM, and ESCA, respectively.In this thesis, CdSe/PPy, CdSe-CdTe/PPy, and CdSe-CdTe-CdSe/PPy semiconductor/polymer nanocomposites have been produced with the electrodeposition process. The combination of electron-conducting semiconductors with hole-conducting polymers into a single composite provides effective charge tra- nsport and allows the expansion of the recombination zone over the composite layer, which may enhance the luminescent properties of the composite. The luminescent properties of the semiconductor/polymer nano-composites can be tuned by using CdSe/CdTe thin films of different thickness, or of different combi- nations. Compared with CdSe/PPy and CdSe-CdTe-CdSe/PPy nano-composites, the nano-composite structure of CdSe-CdTe/PPy was found to possess enhanced luminescent property, which is promising for optoelectronic applications.