Hello, everyone,

I am working with a device that involves a layer of SiO2 sputtered on
top of epitaxially grown GaAs. It appears that there is a large number
of surface states that form at the interface (GaAs-SiO2) that
effectively screen any electric fields that are applied perpendicular
to the surface.

Could anyone point me to some literature on eliminating these surface
states? Also, is there another insulating NIR-transparent material
that would not form such surface states at the interface with GaAs?

To give a bit mode detail, I'm trying to fabricate a capacitor-like
device where the half the dielectric is SiO2 and half is GaAs. It is
very important for the potential to drop linearly in the device so
that the field inside a material would only depend on the dielectric
constant of the material.  What I am getting right now is that all
field is screened by the interface between SiO2 and GaAs.

thank you,
-mikas