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, W., Li, B., He, H., Wang, J., Tam, H., Cheah, K., Cao, X., Wang, Y., Lian, G., & Xiong, G. (2009). The formation of a charge layer at the interface of GaMnAs and an organic material. EPL, 88 (4). https://doi.org/10.1209/0295-5075/88/46002