The Barrier’s Heights and Its Inhomogeneities on Diamond Silicon Interfaces

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 (φ_b) were found to be strongly temperature dependent. The φ_b 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 φ_b were calculated from I-V characteristics using the thermionic emission theory (TE). The plot of φ_b 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 𝜑𝑏 and standard deviations σ were obtained from the plots linearization and read out from intercepts and slopes. They take values 𝜑𝑏 = 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*).

 

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