3C-SiCナノシートにおける量子閉じ込め効果とピエゾ抵抗特性シミュレーション

抄録

The piezoresistivity in beta silicon carbide (3C-SiC) ultra-thin nanosheet with (001) surface orientation has been simulated on the basis of first-principles calculations of model structures. Electronic structure of the 3C-SiC nanosheet model with about 4 nm thickness has been completely verified in terms of the quantum confinement by the projection of the 3-dimensional multi-valley conduction band for bulk 3C-SiC onto the 2-dimensional reciprocal-lattice plane. For the ultra-thin 3C-SiC nanosheet models of less than 2 nm thickness, original features of themselves in electronic state can be observed beyond the quantum confinement concept. The strain response to carrier conductivity of n- or p-doped nanosheet models were calculated using band densities and their effective mass tensors with respect to carrier concentration and temperature. In the p-doped state, much larger longitudinal and transverse gauge factors for [110] direction were evaluated with the same qualitative character as p-type bulk 3C-SiC, on the condition that thickness is more than 2 nm under the quantum confinement effect.