Study on hot-wall-epitaxy-grown 9,10-anthraquinone films

Abstract

ABSTRACT9,10-Anthraquinone films have been prepared by hot wall epitaxy technique onto the glass substrate kept at different temperatures in a vacuum of 1 O Ton. The experimental conditions are optimized to obtain better crystallinity of the films. The films so prepared have been studied for their structural, optical and electrical properties. The JR and NMR studiesconfirmed the formation of 9,10-anthraquinone films. Crystallites as large as 0.61 im are observed in the case of films deposited at 348 K. Observations reveal that the crystallinity of the films increases with increase in substrate temperature. The conduction in these films is found to be ohmic in nature and appears to take place by thermally activated hopping above intermolecular barriers. The electrical conductivity, carrier concentration and drift mobility ofthe films increase withincreases in substrate temperature, whereas activation energy decreases. Analysis of optical absorption measurements onthe films indicates that the interband transition energies lie in the range 3.16-3.44 eV.Keywords: Hot wall epitaxy, organic semiconductors, anthraquinone, scanning electron microscopy, x-ray diffraction,electrical properties and measurements, optical properties.