The explanation of barrier height inhomogeneities in Au/n-Si Schottky barrier diodes with organic thin interfacial layer

Abstract

The forward bias current-voltage (I-V) characteristics of Au/n-Si Schottky barrier diodes (SBDs) with Zn doped poly(vinyl alcohol) (PVA:Zn) interfacial layer have been investigated in the wide temperature range of 80–400 K. The conventional Richardson plot of the ln(Io/T2) versus q/kT has two linear regions: the first region (200–400 K) and the second region (80–170 K). The values of activation energy (Ea) and Richardson constant (A∗) were obtained from this plot and especially the values of A∗ are much lower than the known theoretical value for n-type Si. Also the value of Ea is almost equal to the half of the band gap energy of Si. Therefore, the Φap versus q/2kT plot was drawn to obtain the evidence of a Gaussian distribution (GD) of barrier heights (BHs) and it shows two linear region similar to ln(Io)/T2 versus q/kT plot. The analysis of I-V data based on thermionic emission of the Au/PVA:Zn/n-Si SBDs has revealed the existence of double GD with mean BH values (Φ¯B0) of 1.06 eV and 0.86 eV with standard deviation (σ) of 0.110 eV and 0.087 V, respectively. Thus, we modified ln(Io/T2)−(qσ)2/2(kT)2 versus q/kT plot for two temperature regions (200–400 K and 80–170 K) and it gives renewed mean BHs Φ¯B0 values as 1.06 eV and 0.85 eV with Richardson constant (A∗) values 121 A/cm2 K2 and 80.4 A/cm2 K2, respectively. This obtained value of A∗=121 A/cm2 K2 is very close to the known theoretical value of 120 A/cm2 K2 for n-type Si.

Temperature-dependent electrical properties for graphene Schottky contact on n-type Si with and without sulfide treatment

“…The deviation may be due to the spatially inhomogeneous barriers and potential fluctuations at the interface that consist of low and high barrier areas, that is, the current through the diode will flow preferentially through the lower barriers in the potential distribution. The spatial barrier inhomogeneities in Schottky diodes are described by Gaussian distribution function [31,36,37]. The conventional Richardson plot is modified by Gaussian distribution function as follows [31,37]:…”

“…The spatial barrier inhomogeneities in Schottky diodes are described by Gaussian distribution function [31,36,37]. The conventional Richardson plot is modified by Gaussian distribution function as follows [31,37]:…”

Barrier modification of Au/n-GaAs Schottky structure by organic interlayer

“…This leads to Fermi level pinning, thereby reducing its performance drastically and limiting its application to be used as tailor-made devices. However, the presence of an interfacial layer between the metal contact and the semiconductor can lead to change in band alignment by changing the barrier height (BH) [2,[10][11][12][13][14]. This change is related to many parameters such as the type of the chosen organic compound and its formation, its thickness, the process of surface preparation, the impurity concentration of a semiconductor and the interfacial layerinduced dipole at the M-S interface [13][14][15][16].…”

Analysis of temperature dependent current-voltage and capacitance-voltage characteristics of an Au/V2O5/n-Si Schottky diode

“…The current-voltage characteristic of Au/V 2 O 5 /n-Si SBDs at 145 K is also shown in the inset of figure 2. However, many research groups [6][7][8] have reached up to 80 K using IL of different organic or polymer materials. Again, in order to determine Schottky parameters such as series resistance (R s ), ideality factor and barrier height from the temperature dependent forward bias I-V characteristics we have employed the model of Cheung and Cheung.…”

“…Taşçıoglu et.al. 6 reported that organic IL in MS structures improved the Schottky diode properties. A PVA film doped with different concentrations of nickel (Ni) and zinc (Zn) as IL between metal and semiconductor was also reported.…”