1) The room temperature electrical conductivity of intrinsic silicon is 4 x 104 (m) An extrinsic n-type silicon material is desired having a room temperature conductivity of 150 (2m). Specify a donor impurity type that may be used as well as its concentration in atom percent to yield these electrical characteristics Assume that the electron and hole mobilities are the same as for intrinsic material and that at room material the donor impurities are exhausted [15 marks)