As we know the mobility of carriers strongly depends on the crystaline orientioan.
My question is when in material setup of DEVICE we select for example the mobility of holes=400 v/cm2 and electrons = 1200 v/cm2. this mobility is in which direction? It is the mobility of carriers in their moving direction?
In attached image the path of elctron and holes is shown (for my solar cell), so how can I make sure the mobility that I select is in carriers mvoing direction?
This mobility is in which direction?