Thin Film Formation $(20$ points$)$

A fresh aluminum surface is very reactive to oxygen, so that the sticking coefficient of O$\_(2)$ is nearly $1.$

How long could a fresh aluminum surface be exposed to air to insure less than a monolayer accumulation of oxygen $($assume $1$ monolayer $=3$xx$10^(15)$atoms$//$cm$^(2))^(9))(4$ pts$)$

What would be the partial pressure of O$\_(2)$ have to be to keep the aluminum surface clean $($i$.$e$.,$ less than one monolayer of oxygen$)$ for an hour? $(4$ pts $)$

How would you pump down to achieve the pressure calculated in $2)?$ Elaborate the process. $(2$ pts$)$

Explain the operating principle of the pump$($s$)$ you would recommend. $(2$ pts$)$

What kind of gauge$($s$)$ would you recommend to measure such pressure of the vacuum chamber and why? $(2$ pts$)$

Explain the difference between top$-$down and bottom$-$up approaches for nanomaterial growth and list at least two techniques. $(6$ pts$)$