(Solved): 3. A pn junction (diode) with a cross-sectional area of \( 1 \mathrm{~mm}^{2} \) has \( \mathrm{I} ...

3. A pn junction (diode) with a cross-sectional area of \( 1 \mathrm{~mm}^{2} \) has \( \mathrm{I}_{\mathrm{S}}=10 \mathrm{fA} \) at room temperature (300 K). This pn junction is planned to be used on the Moon in a circuit with a forward bias voltage of \( 0.72 \mathrm{~V} \). Calculate the ratio between day \( \left(T=260 \mathrm{~F}^{0}\right) \) and night \( \left(T=-280 \mathrm{~F}^{0}\right) \) for (a) Saturation current \( I_{S} \) (assume \( D_{n}, D_{p}, L_{p} \) and \( L_{n} \) are independent to temperature) (20 points) (b) Forward bias current I IF. (30 points).