1. The problem statement, all variables and given/known data Silicon is doped with an Aluminum Concentration of 2 X 10^16 cm^-3 What are the free electron and hole concentrations at room temperature? What are the electron and hole mobilities at 300K? What is the majority carrier? What is the minority carrier? 2. Relevant equations n_0 * p_0 = (n_i)^2 [[(Concentration of Electrons) * ( Hole Concentration) = (Intrinsic Carrier Concentration)^2]] n_i = 1.5 X 10^10 cm^-3 [[For Silicon]] 3. The attempt at a solution This is actually for my electronics class, but this is more of a chemistry type question so I posted here. I've missed few lectures and I'm already lost. Can anyone just start me off, provide me some hints and equations I should use to find the mobility? As for the majority/minority carrier part, I understand that if the semiconductor is n-type, electrons are the majority carrier and holes are the minority carriers and the opposite for the p-type. How do you tell which type of material this is?