Dear Ning,

Thank you for your reply. Because I read one science
paper using the native aluminium oxide as the
insulaotr for the carbon nanotube transistor and they
did not mention any special treatment. I try to heat
it up to 400oC, hopefully I will get a thicker oxide.

Sincerely yours,
CHEN Hongzhi

--- "Ning Wu (nwu@Princeton.EDU)" 
wrote:

> Hongzhi,
>
> I believe that native Aluminium oxide layer is very
> thin, just like native silicon oxide, which may not
> be thick enough to be used as a insulating layer.