In this paper, a theoretical study of single electron transistor (SET) based on silicon quantum dot (Si-QD) has been studied. We have used a novel approach based on the orthodox theory. We studied the energy-level broadening effect on the performance of the SET, where the tunnel resistance depends on the discrete energy. We have investigated the I-V curves, taking into account the effects of the energy-level broadening, temperature and bias voltage. The presence of Coulomb blockade phenomena and its role to obtain the negative differential resistance (NDR) have been also outlined. DOI: 10.21883/FTP.2017.12.45191.8239