The comparative electrical characteristics of Au/n-Si (MS) diodes with and without a 2% graphene cobalt-doped Ca3Co4Ga0.001Ox interfacial layer at room temperature

• Au/n-Si (MS) and Au/2% graphene cobalt (GC)-doped (Ca3Co4Ga0.001Ox)/n-Si (MPS) type diodes were fabricated.
• The 2% GC-doped (Ca3Co4Ga0.001Ox) interfacial layer prevented reaction and inter-diffusion between Au and n-Si.
• The magnitude of Nss for the MPS-type diode was one order of magnitude lower than that of the MS-type diode.
• The interfacial 2% GC-doped Ca3Co4Ga0.001Ox layer enhanced the diode performance.

To investigate the effect of 2% graphene cobalt (GC)-doped (Ca3Co4Ga0.001Ox) interfacial layer on the main electrical parameters, Au/n-Si (MS) Schottky barrier diodes (SBDs) were fabricated with and without this inter-facial layer. Using forward and reverse bias current–voltage (I–V) measurements, selected electrical parameters of these diodes were obtained and compared at room temperature. The energy density distribution profiles of the surface states (Nss) were obtained from the forward-bias I–V data by taking into account the voltage-dependent effective barrier height (Φe) and ideality factor (n(V)). The value of Nss for the MPS-type diode is one order of magnitude lower than that of the MS diode. These results indicated that the 2% GC-doped (Ca3Co4Ga0.001Ox) interfacial layer prevents reaction and inter-diffusion between Au and n-Si as well as passivating the active dangling bonds at the semiconductor surface. In addition, the voltage-dependent profile of the resistance (Ri) was also obtained for the two diodes from the I–V data using Ohm's law. In both the MS- and MPS-type diodes, an apparent exponential increase in Nss was observed from the mid-gap toward the bottom of the Ec. The experimental results show that the existence of Nss, Rs, and the interfacial layer has a great effect on the electrical characteristics of these structures. The value of the depletion layer width was obtained from C–V measurements at 300 kHz for the two diodes. The obtained results show that the GC-doped (Ca3Co4Ga0.001Ox) interfacial layer considerably enhances the diode performance.

Figure optionsDownload as PowerPoint slide