Title :
The local energy level of polyimide
Author :
Li, Yuhua ; Liu, Zhe ; Ren, Jinchang
Author_Institution :
Dept. of Electr. Eng., Xi´an Jiatong Univ.
Abstract :
Photoconduction and photoabsorption experiments on polyimide films with different imidities and crosslinking densities are described. Initially the energy gap was found to be larger than 10.35 eV, and the thresholds of photoinjection for gold and aluminium electrodes were 1.65 eV and 0.9 eV, respectively. By changing the molecular morphology of the sample, changing the polarity of the radiated electrode, and precharging the sample under high voltage, it was shown that there are many kinds of local energy levels with different energy levels in the forbidden band. Local levels were found to be closely related to the chemical and physical morphology of the material, among which the level originating from the imide group is the deepest level and acts as an electron donor. The density of the remaining levels decreases with the increase of imidity and crosslinking density
Keywords :
energy gap; localised electron states; photoconductivity; polymer films; ultraviolet spectra of organic molecules and substances; visible spectra of organic molecules and substances; Al electrode; Au electrode; chemical morphology; crosslinking densities; electrode polarity; electron donor; energy gap; forbidden band; imide group; local energy level; molecular morphology; photoabsorption; photoconduction; photoinjection thresholds; physical morphology; polyimide films; precharging; Aluminum; Chemicals; Electrodes; Electrons; Energy states; Gold; Morphology; Photoconductivity; Polyimides; Voltage;
Conference_Titel :
Properties and Applications of Dielectric Materials, 1988. Proceedings., Second International Conference on Properties and Applications of
Conference_Location :
Beijing
DOI :
10.1109/ICPADM.1988.38410
