Controlling of electrical characteristics of Al/p-Si Schottky diode by tris(8-hydroxyquinolinato) aluminum organic film

We study how tris(8-hydroxyquinolinato) aluminum organic semiconductor layer at p-silicon/Al interface can affect electrical transport across this interface. Al/Alq3/p-Si device shows a good rectifying behavior with an ideality factor value of 1.95. The barrier height values obtained from I–V and Norde method were found to be 0.84 and 0.82 eV, respectively. This indicates that the barrier height obtained from Norde method is lower than that of barrier height value obtained from I–V due to the series resistance effect. The modification of the interfacial potential barrier for Al/p-Si diode was achieved using an interlayer of the Alq3 organic semiconductor and this is ascribed to the fact that the Alq3 interlayer increases the effective barrier height, because of the interface dipole induced by passivation of the organic layer. The frequency dispersion in capacitance and conductance can be interpreted in terms of the series resistance and interface state density values. The series resistance of the diode was changed from 9 kΩ to 1 kΩ with increasing frequency. The distribution profile of Rs–V gives a peak at low frequencies in the depletion region and disappears with increasing frequency.