Laterally inhomogeneous barrier analysis of the methyl violet/p-Si organic/inorganic hybrid Schottky structures

Abstract

In this work, we have investigated the electrical characteristics, such as current–voltage ( I–V) and capacitance–voltage ( C– V) measurements, of identically prepared crystal violet/p-Si Organic/Inorganic (OI) Schottky structures formed by evaporation of organic compound solution to directly p-Si semiconductor substrate. It has been seen that the crystal violet organic dye thin film on the p-Si substrate has exhibited a good rectifying behavior. The barrier heights (BHs) and ideality factors of all devices have been calculated from the electrical characteristics. Although the diodes were all identically prepared, there was a diode-to-diode variation: the effective barrier heights ranged from 0.6 ± 0.1 to 0.8 ± 0.1 eV, and the ideality factor from 1.6 ± 0.4 to 3.5 ± 0.4. The barrier height versus ideality factor plot has been plotted for the OI devices. Lateral homogeneous BH was calculated as a value of 0.7 eV from the observed linear correlation between BH and ideality factor, which can be explained by laterally inhomogeneities of BHs. The values of barrier height and acceptor doping concentration yielded from the reverse bias C– V measurements ranged from 0.7 ± 0.1 to 1.3 ± 0.1 eV and from (4.7 ± 0.8) × 10 14 to (8.1 ± 0.8) × 10 14 cm −3, respectively. The mean barrier height and mean acceptor doping concentration from C– V characteristics has been calculated 1.0 eV and 5.9 × 10 14 cm −3, respectively. It has been seen that the mean BH value of 0.7 eV obtained for the Al/methyl violet/p-Si contact is significantly larger than BH values of the conventional Al/p-Si Schottky diodes. Thus, modification of the interfacial potential barrier for metal/Si diodes has been achieved using a thin interlayer of the methyl violet organic semiconductor; this has been ascribed to the fact that the methyl violet interlayer increases the effective barrier height by influencing the space charge region of Si.