Modelling of structural and threshold voltage characteristics of randomly doped silicon nanowires in the Coulomb-blockade regime

We report on the theoretical investigation of how geometrically uniform hig hly doped silicon nanowires can break up into a series of islands that exhi bit Coulomb blockade. By using a newly developed numerical simulation in wh ich random ionized dopants are introduced explicitly and the electron distr ibution is calculated self-consistently under the Thomas-Fermi approximatio n, we demonstrate natural formation of electron islands in the nanowires ow ing to the random dopant potential. We study the quasi-one-dimensional natu re of the electron islands formed in the nanowires. The offset charge effec ts on the current threshold of the nanowire transistors are then investigat ed by feeding the derived structural parameters such as inter-island capaci tance and tunnel resistance into a Monte Carlo single electron transport si mulator. We show that the overall threshold voltage distribution can roughl y be described as a two-'macro'-island system despite a complex series of m ultiple electron islands.