Electric field → charge density

The electric field in a silicon diode is described by,

 [V/m].

Here $x$ and $y$ are measured in meters. What is the charge density in this region?

The relative dielectric constant of silicon is $\epsilon_r=12$. The permeability constant is $\epsilon_0=8.85\times 10^{-12}$ F/m.

$\rho =$ [C/m³]