  Here, we report an alternative route to achieve two dimensional electron gas
(2DEG) in a semiconductor structure. It has been shown that charge accumulation
on the side facets can lead to the formation of 2DEG in a network of c-axis
oriented wedge-shaped GaN nanowalls grown on c-plane sapphire substrate. Our
study reveals that negative charges on the side-facets pushes the electron
cloud inward resulting in the formation of 2DEG in the central plane parallel
to the wall height. This confinement is evidenced from several orders of
magnitude enhancement of electron mobility as compared to bulk, observation of
weak localization effect in low temperature magneto-transport studies as well
as the reduction of both the elastic and inelastic scattering rates with the
average width of the walls. Importantly, the phase coherence length has been
found to be as high as 20 {\mu}m, which makes the system potentially
interesting for spin-tronics. Schrodinger and the Poisson equations are solved
self-consistently taking into account the surface charge accumulation effect.
The result indeed shows the 2D quantum confinement of electrons even for 40 nm
of wall-width.
