Effects of Rapid Thermal Annealing on the Structural, Optical, and Electrical Properties of Au/CuPc/n-Si (MPS)-type Schottky Barrier Diodes

The effects of rapid thermal annealing temperature on structural, morphological, and optical properties of copper phthalocyanine (CuPc) films on n-Si are investigated. The deposited CuPc films on n-Si substrate form nanoparticles and are slightly elongated with an increase in surface roughness with increase in annealing temperature due to the aggregation of the native grains. The electrical and current transport properties of a fabricated Au/CuPc/n-Si metal-polymer-semiconductor (MPS)-type Schottky barrier diodes (SBDs) are explored at various annealing temperatures (range 100–300 °C) by current–voltage (I–V) and capacitance–voltage (C–V) measurements. Results reveal that the estimated barrier height decreases with increasing annealing temperature and could be ascribed to the diffusion of Au atoms into CuPc films transferring negative charges to the molecule inducing an n-type doping of the organic film. An analysis of the forward log (I)–log (V) plot of Au/CuPc/n-Si (MPS)-type SBDs indicated the carrier transport domination by ohmic conduction in the lower bias and by the space-charge-limited current (SCLC) transport mechanism at higher bias regions irrespective of annealing temperatures that might be related to additional traps initiating from the CuPc. Poole–Frenkel emission governs the current transport in the reverse bias regardless of annealing temperature.