Electronic transport properties of doped sawtooth - sawtooth penta silicon dicarbide nanoribbons

Abstract

This paper presented the electronic transport properties of one dimensionally sawtooth – sawtooth edge pentagonal silicon dicarbide nanoribbons (SS-pSiC2) doped n-type (nitrogen: N) atoms and p-type (bore: B) atoms based on the combination of the density functional theory and the nonequilibrium Green’s function formalism. Electronic properties such as the energy band structure (BS), the density of state (DOS) and partial density of state (PDOS) were investigated and compared with the undoped one. The results showed that N played a role in contributing to the Fermi-level optical states that made the system transition from semiconductor to metal. The contribution of the state of the H atom was recognized but this one was very small. When doping B, the material system possessed the metallic properties because the Fermi level crossed the valence subregion. With the Fermi level falling to the top of the valence band, the contribution of the valence electronic states of B was mainly near the Fermi leve. This showed that B was a p-type impurity. The electron transport properties were also investigated, specifically the Volt-Ampere characteristic (I‒V curve) of bipolar devices based on SS-pSiC2 which was passivated by H atoms on the boundary. When doping N, the current appeared as soon as the bias voltage had just a small value. This was the Volt-Ampere characteristic of the metal. The current value also tended to saturate when the voltage was high. The current was about two orders of magnitude larger than the undoped case but lower than the current value of SS-PGNR. When doping B, the current value tended to saturate earlier than the case of N doping when the voltage was high. The current was about an order of magnitude smaller than the n-type doping case. This meant that the amperage obtained with a predominantly hole carrier was smaller than that of a predominantly electron carrier. The results showed that the electronic structure and the current of the studied samples strongly depended on the doping element as well as on the doping type. When doping, the studied system changed from the semiconductor to metal. Furthermore, with p-type doping, the flow of mainly hole carriers was one order of magnitude lower in intensity than that of mostly electron carriers (n-type doping).