Explain with the depletion layer concept why a p-n junction allows current flow only in one direction — JEE Physics
Explain with the depletion layer concept why a p-n junction allows current flow only in one direction. If forward bias is 0.7 V and the reverse saturation current $I_0 = 1\ \mu$A, find the diode current at room temperature ($T = 300$ K, $k = 1.38 \times 10^{-23}$ J/K).
1 Answer
VAVidaara Admin
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· 2mo ago
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Using Shockley equation:
$$I = I_0\left(e^{eV/kT} - 1\right)$$
$$\frac{eV}{kT} = \frac{1.6\times10^{-19} \times 0.7}{1.38\times10^{-23} \times 300} = \frac{1.12\times10^{-19}}{4.14\times10^{-21}} = 27.05$$
$$I = 10^{-6}(e^{27.05} - 1) \approx 10^{-6} \times 5.5\times10^{11} = 5.5 \times 10^5\ \mu A \approx 0.55 A$$
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Discussion (2)
AK
Brilliant explanation, the substitution step is what I kept missing.
A
This is exactly the kind of step-by-step I needed. Respect.