Electrical and structural properties of refractory metal Mo/poly(3-methylthiophene) Schottky barrier diodes

We present the results of a study of Mo/poly(3-methylthiophene)/Pt Schottky diodes. The Mo contact is sputtered onto electrochemically deposited poly(3-methylthiophene) (P3MT). Grazing incidence X-ray diffraction (GIXD) analysis shows that P3MT is amorphous. X-ray photoelectron spectroscopy (XPS) studies reveal that the Mo/P3MT interface is extremely diffuse with a great Mo penetration in the P3MT layer. However, no chemical reaction is observed. The rectification ratio of these devices at ±1 V is 620. The capacitance–frequency measurements show that the capacitance is frequency dependent. This behavior is explained on the basis of the amorphous nature of the polymer. The value of the density of states near the Fermi level N0 deduced from the capacitance measurements at low frequencies is 1.2×1017 cm−3 eV−1.