Department of Physics
The formation of a charge layer at the interface of GaMnAs and an organic material
The interface formed between the ferromagnetic semiconductor GaMnAs and the organic semiconductor N,N'-diphenyl-N,N'-bis(1-naphthyl)(1,1'-biphenyl)-4,4'- diamine (NPB) was investigated using current transport measurement and ultraviolet photoemission spectroscopy (UPS). The hole injection barrier at a GaMnAs and NPB interface was measured as 0.77eV by modelling the measured current density-voltage (J-V) characteristics in a GaMnAs/NPB/Al structured device. The vacuum level shift at a GaMnAs/NPB interface was deduced to be 0.54 eV, indicating that a dipole layer exists at the interface. A UPS study gave a vacuum level shift of 0.53 eV and a band offset between the GaMnAs valence band and the highest occupied molecular orbital of NPB of 0.79 eV, in good agreement with the results of J-V measurements. We attribute the vacuum level shift to charge transfer across the interface. Copyright © EPLA, 2009.
Source Publication Title
European Physical Society
Link to Publisher's Edition
Chen, Wenjin, Baikui Li, Hongtao He, Jiannong Wang, Hoi Lam Tam, Kok Wai Cheah, Xiancun Cao, Yuqi Wang, Guijun Lian, and Guangcheng Xiong. "The formation of a charge layer at the interface of GaMnAs and an organic material." EPL 88.4 (2009).