Let's put the question in the context of growing Bi2Se3 thin film. Say, we would like to grow 20 quintuple layers of Bi2Se3 using MBE. The flux rate of Bi dominates that of Se for the purpose of calculating the growth time. Say, the flux rate of Bi is 0.002 nm/sec. Bi crystal has density of 9.8 g/cm^3 and the Z-factor for the QCM is 0.79. One quintuple layer of Bi2Se3 is about 0.95 nm. Then how do we find out how much time we need to complete the 20-layer quintuple-layer growth?
I am thinking about converting the flux rate of Bi to (number of Bi layers)/second since one quintuple layer of Bi2Se3 consists of two layers of Bi. But I have difficulty doing such conversion because I am not sure whether the lattice structure of Bi comes in this calculation and (if so) how exactly it does. I am not sure whether I am over-complicating the calculation, either.