We usually grow h-BN on Cu foil using CVD system.

I don't know what is the problem.

Typically, Our Cu foil is poly-crystalline with 100um thickness.

When we take sample out in the quartz tube of CVD, the temperature is naturally cooling down to 300ºC and maintaining 5 Torr in the N2 atmosphere.

Sample 1 is a Cu foil before growth of h-BN.

Sample 2 is a h-BN/Cu and take out at 300ºC

(non-mirror like surface)

Sample 3 is a h-BN/Cu and take out at 25ºC (under 1 mTorr)

(burned surface??)

So, we want to know about the difference of surface between before and after growth of h-BN.