In this work, the electrical parameters of the polycrystalline diamonds' p-PCD/n-Si heterojunction were investigated using temperature-dependent current-voltage (I-V) characteristics. In the temperature range of 80-280 K, the ideality factor (n) and energy barrier height (φb) were found to be strongly temperature dependent. The φb increases with temperature rise, while the n value decreases. The observed dependencies are due to imperfections at the interface region of a heterojunction and the non-homogeneous distribution of the potential barrier heights. Values of the φb were calculated from I-V characteristics using the thermionic emission theory (TE). The plot of φb versus 1/2 kT revealed two distinct linear regions with different slopes in temperature regions of 80-170 K and 170-280 K. This indicates the existence of a double Gaussian distribution (DGD) in heterojunctions. Parameters such as mean barrier heights φ¯b and standard deviations σ were obtained from the plots linearization and read out from intercepts and slopes. They take values φ¯b = 1.06 eV, σ = 0.43 eV, respectively. The modified Richardson plot is drawn to show the linear behavior in these two temperature ranges, disclosing different values of the effective Richardson constants (A*).
Keywords: I-V characteristics; Raman spectroscopy; XRD; energy barrier height; ideality factor; p-PCD/n-Si heterojunction; polycrystalline diamond film.