GATE EC 2021 Set 1 Q42 — Electronic Devices

A silicon $P-N$ junction is shown in the figure. The doping in the $P$ region is $5\times10^{16}\:cm^{-3}$ and doping in the $N$ region is $10\times10^{16}\:cm^{-3}$. The parameters given are

• Built-in voltage $\left ( \Phi _{\text{bi}} \right )$ = $0.8\:V$
• Electron charge $(q)$ = $1.6\times10^{-19} C\:$
• Vacuum permittivity $\left ( \varepsilon _{0} \right )$ = $8.85\times10^{-12}\:F/m$
• Relative permittivity of silicon $\left ( \varepsilon _{\text{Si}} \right )$ = $12$

The magnitude of reverse bias voltage that would completely deplete one of the two regions ($P$ or $N$) prior to the other (rounded off to one decimal place) is ______________________ $V$.