A.c. and d.c. conduction processes in octakis[(4-tert-butylbenzylthio)-porphyrazinato]Cu(II) thin films with gold electrodes

Bulletin of materials science

Ulvi Avciata³  Ahmet Altindal³  Bahadir Keskin¹  Ahmet Gül² 

[1] Department of Chemistry, Yildiz Technical University, 34210 Istanbul, Turkey$$Department of Chemistry, Yildiz Technical University, 34210 Istanbul, TurkeyDepartment of Chemistry, Yildiz Technical University, 34210 Istanbul, Turkey$$;Department of Chemistry, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey$$Department of Chemistry, Istanbul Technical University, 34469 Maslak, Istanbul, TurkeyDepartment of Chemistry, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey$$;Department of Physics, Yildiz Technical University, 34210 Istanbul, Turkey$$Department of Physics, Yildiz Technical University, 34210 Istanbul, TurkeyDepartment of Physics, Yildiz Technical University, 34210 Istanbul, Turkey$$

关键词: Porphyrazine;    a.c. conductivity;    correlated barrier hopping;    spin coating;    tunnelling.;   

DOI  :  

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

The d.c. and a.c. electrical transport properties of Au/Pz/Au devices with various thickness of Pz(octakis[(4-tert-butylbenzylthio)-porphyrazinato]Cu(II)) layer have been investigated. Measurements revealed that, in contrast to previously investigated Au/Pc/Au structures, low voltage d.c. behaviour of the films can be described by the field-lowering mechanisms with a $log$(𝐽) ∝ ð‘�??^1/2 current density-voltage characteristics under forward and reverse bias. For high reverse voltages, the observed ln (𝐽/ð‘�??²) - 1/ð‘�?? characteristics indicated that the origin of conduction mechanism is Fowlerâ€�?�Nordheim tunnelling (FNT). On the other hand, the voltage dependence of current density at the higher forward-voltage region indicates that the mechanism of conduction in Au/Pz/Au devices is space charge limited conduction dominated by exponential trap distribution. A thickness independent barrier height was observed for tunnelling, while the total trap concentration show a general tendency to decrease with increasing film thickness. The a.c. conductivity showed two regions in the ln (𝜎_a.c.) - ln(ð‘�??) plots having different slopes, leading to the conclusion that for low frequency region, the dominant conduction mechanism is a small polaron tunnelling at all temperatures, whereas for high frequency region, correlated barrier hopping model is the dominant mechanism in the investigated devices.

【 授权许可】

Unknown