Modified electrical characteristics of Pt/n-type Ge Schottky diode with a pyronine-B interlayer

• Pyronine-B interlayer modified the electrical properties of Pt/n-Ge Schottky diode.
• PYR-B layer formed on the Ge substrate had a smooth interface.
• PYR-B interlayer reduced the interface state density in the Pt/n-Ge Schottky diode.
• Reverse current mechanism in Pt/n-Ge and Pt/PYR-B/n-Ge structures was investigated.

The electrical characteristics of a Pt/n-type Ge Schottky diode with a pyronine-B (PYR-B) interlayer prepared by spin coating was investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements. It was observed that the barrier height of Pt/PYR-B/n-type Ge (0.65 eV) was higher than that of the conventional Pt/n-type Ge Schottky diode (0.58 eV). This is attributed to the fact that the organic interlayer increases the effective barrier height by influencing the space-charge region of Ge. The introduction of the PYR-B interlayer led to a reduction of the interface state density in the Pt Schottky contact to n-type Ge. The electric field dependence of the reverse leakage current revealed that Schottky emission and Poole–Frenkel emission mechanisms dominated the reverse current in the Pt/n-type Ge and Pt/PYR-B/n-type Ge Schottky diodes, respectively.