M.Sc Thesis

M.Sc StudentPreezant Yevgeni
SubjectElectrical Properties of the Contact Region of Polymeric
Semiconductor Devices
DepartmentDepartment of Electrical and Computer Engineering
Supervisor PROF. Nir Tessler


The field of polymeric semiconductors light emitting devices is emerging field in modern microelectronics. Relative simplicity of polymer processing in compare to traditional silicon-based electronics, enormous diversity of polymeric compounds drew a large attention to commercial application of polymer-based devices. In spite of a vast amount of experimental data there is no sufficient integrate theory for description of physics of such devices.

It’s widely accepted that the mechanism of conductivity in these polymers is based on the motion of charged defects within the disordered conjugated net. The charge carriers’ transport is transport by hopping between neighboring regions of conjugation. Experimental investigation of conjugated polymer devices reveals some features that are exclusive for semiconducting conjugated polymers. Such as field-dependent mobility and weak temperature dependence of injection rate for high barriers metal-polymer contacts. In this work we demonstrate that widely known models of injection from realm of inorganic microelectronic devices can’t be used for injection phenomena explanation. Moreover, the field-dependence of mobility also demands special explanation.  In order to explain observed effects both qualitatively and quantitatively we had built integral physical picture of injection and transport in polymeric devices. Basing on the first-principle physical assumption about the microscopic nature of transport we obtained macroscopic characteristics of polymer and finally we simulated the device behavior. During the course of the research we carried out both experimental and numerical investigations of polymer PEDOT/MEH-PPV/Metal hole-only diode devices in a large span of temperatures and device thickness’. Some modifications were introduced to numerical technique. Reasonable degree of agreement between experiment and theory is achieved for wide range of parameters.