Capacitance-voltage characteristics of LB thin films incorporating cds nanoparticles

Abstract

Two types of Langmuir-Blodgett (LB) thin films based on hybrid organic-inorganic materials sandwiched between metal and semiconductor were fabricated. The novel films were 40 layers Y-type LB films of Cd-salt stearic acid (CdSt2). The second type of films was formed after the treatment of CdSt2 films with H2S gas over a period of 12 hours at room temperature to grow CdS nanoparticles within the stearic acid matrix. The capacitance-voltage (C-V) measurement of CdSt2 LB films exhibit a significant dependence on the measurement frequency in the accumulation region due to high DC leakage currents. By embedding CdS nanoparticles into the stearic acid matrix, less frequency dependent C-V curves were obtained. The problem in determining the true insulator capacitance due to frequency dispersion was overcome by using the Yang's model. The corresponding dielectric constant of LB films of CdSt2 was found to be 2.3 and increased to 5.1 when embedded with CdS nanoparticles.