Semiconductor based electronic devices are being scaled into nano-meters of dimension. Present electronics demands the better material which will be reliable than the previous used semiconductor materials such as silicon. Silicon has now the less capability and also not optimum in all respect. Gallium Arsenide is now emerging good choice the other semiconductor like silicon and germanium. This work presents the basic physics of the single electron transistor (SET) using GaAs semiconductor material. The coulomb effect calculations in the SET, mobility of GaAs in the SET and permittivity vs. frequencies in order of THz depicts that GaAs SET may be used in the high frequency communication devices.