The silicon sample with unit cross-sectional area shown below is in thermal equilibrium. The following information is given: $\text{T}=300 \mathrm{~K}$, electronic charge $=1.6 \times 10^{-19} \mathrm{C}$, thermal voltage $=26 \; \mathrm{mV}$ and electron mobility $=1350 \mathrm{~cm}^{2} / \text{V-s}$.
The magnitude of the electron drift current density at $x=0.5 \; \mu \mathrm{m}$ is
- $2.16 \times 10^{4} \mathrm{~A} / \mathrm{cm}^{2}$
- $1.08 \times 10^{4} \mathrm{~A}/{\mathrm{cm}^{2}}$
- $4.32 \times 10^{3} \mathrm{~A} / \mathrm{cm}^{2}$
- $6.48 \times 10^{2} \mathrm{~A} / \mathrm{cm}^{2}$
