Influence of Preparation Conditions on Electrical Properties of the Al/Alq3/Si Diode Structures

Abstract

Hybrid organic-inorganic diode structures, Al/Alq3/n-Si and Al/Alq3/p-Si based on thin films of tris(8-hydroxyquinoline) aluminum (Alq3) have been investigated. The Alq3 films were evaporated in vacuum and spin coated onto patterned areas of crystalline n- and p-type Si substrates with chemically removed native SiO2 layer. Current-voltage characteristics of the diode structures demonstrated improved rectification property compared to similar Al/n-Si and Al/p-Si device structures. Increased barrier height values (0.90 eV ÷ 1.1 eV and 0.77 eV ÷ 0.91 eV for the Al/Alq3/n-Si and Al/Alq3/p-Si device structures, respectively) certified presence of an interface dipole induced by the organic interlayer. Non-ideal behavior of forward current-voltage characteristics has been explained assuming non-uniformity of barrier height, presence of interface states, and influence of the organic film on diode series resistance and space charge limited current. DOI: http://dx.doi.org/10.5755/j01.ms.19.4.2733

Keywords

• organic-inorganic heterostructures
• vapour deposition
• spin coating
• Alq3 thin film
• Schottky thermionic emission