ELECTRONIC-PROPERTIES OF SEMICONDUCTOR-INSULATOR INTERFACES IN A THIN-FILM SIO2 A-SI-H/LANGMUIR/BLODGETT FILM TRANSISTOR STRUCTURE/

A double sided thin-film field-effect transistor was constructed from the following structure: SiO2/a-Si:H/Langmuir-Blodgett (LB) film. The LB film was made of a polymer with a comb-like structure and containin g cholesterin. The field-effect mobility in the conducting channel of the transistor along the LB film surface was 30 times higher than alon g the SiO2 Surface. The activation energies of conduction in the trans istor channels were 0.44 and 0.65 eV, respectively. The results obtain ed indicated a high density of states at the a-Si:H/SiO2 interface, co mpared with the a-Si:H/LB-film interface, which was related to the met hods used to form these interfaces. Amorphous hydrogenated silicon was deposited on SiO2 by a plasma-chemical method, while the LB film was deposited on a-Si:H by transfer of a highly ordered quasi-two-dimensio nal liquid crystal from the surface of water. The high quality of the LB films was confirmed by examining them in a scanning atomic-force mi croscope.