Electrical properties of Pt/n-type Ge Schottky contact with PEDOT:PSS interlayer

The effect of poly (3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) interlayer on the Schottky barrier parameters of Pt/n-type Ge Schottky contacts was investigated. The PEDOT:PSS interlayer in between Pt and n-type Ge influences the space charge region of the Pt/n-type Ge Schottky junction, leading to increase in the barrier height. Due to interface dipoles and lateral barrier inhomogeneities caused by the presence of PEDOT:PSS interlayer, Pt/PEDOT:PSS/n-type Ge Schottky contact showed a deviation from the ideal thermionic emission model of the carrier transport at the metal/semiconductor junction. From the reverse current–voltage (I–V) characteristics, the Poole–Frenkel emission and Schottky emission were found to be the dominating carrier conduction mechanisms of Pt/PEDOT:PSS/n-type Ge Schottky contact at lower and higher reverse biases, respectively.

► PEDOT:PSS interlayer led to increase in Schottky barrier height of Pt/n-Ge Schottky diodes.
► Inhomogeneity of Schottky barrier heights across the contact caused by PEDOT:PSS interlayer.
► Transition of carrier conduction mechanism from Poole–Frenkel emission to Schottky emission at a higher bias range.