Chemical analysis of a silicon crystal reveals gallium at a level of atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free carriers/cm3) in this Si crystal?

To determine the density of free charge carriers in a silicon crystal, we first need to know the concentration of gallium atoms in atomic percent. However, it seems that the value for the concentration is missing in your question. Please provide that information so that I can proceed with the calculation.