Field Effect Mobility of <font>F</font>₁₆<font>PcCu</font> Films in Various Gas Atmospheres

Abstract

The electron mobility of hexadecafluorophthalocyaninato-copper ( F 16 PcCu ) films was evaluated based on field effect measurements in vacuum and in various gas atmospheres. An Arrhenius plot of the mobility showed that the carrier transport followed a thermally activated hopping mechanism with an activation energy of 0.28 eV. The mobility evaluated for freshly prepared films in ultrahigh vacuum was 2.0 × 10 −3 cm 2 V −1 s −1 at room temperature. The electrical conductivity and carrier density were 4.4 × 10 −5 S cm −1 and 1.4 × 10 17 cm −3 respectively. The high carrier density indicated the existence of impurities acting as electron donors in the films. The field effect carrier mobility increased to 5.7 × 10 −3 cm 2 V −1 s −1 in NH 3 atmosphere (100%, 1 atm) and decreased by 75% in the presence of O 2 gas (100%, 1 atm). A quick recovery of mobility was observed when the gas molecules were evacuated, indicating a low capability of gas adsorption.