I'm trying to find carrier concentration from mott schottky using this formula :

Nd = 2/e* ε0 * εr(material dielectric constant)*A2*Slope

where

ε0 (8.85E − 12 F m−1) is the vacuum permittivity, A (m) is the exposed area of the material, e (1.60E − 19 C) is the electronic charge, Nd is carrier conc.

Can someone tell me the dielectric constant value .