Double Injection Current Transients in a-Si:H

Abstract

Many organic materials have been synthesized recently, especially for electronic applications (light emitting diodes, solar cells, etc.), therefore new diagnostic methods and improvement of existing ones are needed for testing these materials. One of methods for charge carrier transport studies is double injection (DoI) current transient technique. It allows to investigate charge carrier mobilities, recombination [1, 2] and trapping features [3] in the disordered materials. This experimental technique is very simple as compared to other methods. If the trapping is not significant (or absent), the sum of charge carrier mobilities (μfast + μslow), the mobility of the slowest carriers and bimolecular recombination coefficient could be determined [4]. In this work we demonstrate new possibilities of DoI technique in the case when trapping cannot be neglected. DoI method was applied to investigate the charge carrier transport in a-Si:H. Because a-Si:H is the well investigated material, we can directly compare the obtained results with the known ones and make conclusion about its applicability. DoI technique was also used in the investigation of the trapping features of new organic materials for bulk heterojunction solar cells [5].