The depletion region of a p-n junction contains: -

Under forward bias, the depletion region: <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 300 100" style="max-width:300px;margin:0.5em auto;display:block;"> <title>Forward bias narrows depletion region compared to no bias</title> <rect width="300" height="100" fill="#faf9f5" rx="6"/> <!-- No bias --> <rect x="20" y="15" width="50" height="30" fill="none" stroke="#c6613f" stroke-width="1.5" rx="2"/> <text x="30" y="35" font-size="10" font-family="sans-serif" fill="#c6613f">p</text> <rect x="110" y="15" width="50" height="30" fill="none" stroke="#788c5d" stroke-width="1.5" rx="2"/> <text x="123" y="35" font-size="10" font-family="sans-serif" fill="#788c5d">n</text> <rect x="68" y="15" width="44" height="30" fill="#14140f" fill-opacity="0.08" stroke="#14140f" stroke-width="1" stroke-dasharray="3,2"/> <text x="62" y="58" font-size="8" font-family="sans-serif" fill="#14140f">No bias (wide)</text> <!-- Forward bias --> <rect x="180" y="15" width="50" height="30" fill="none" stroke="#c6613f" stroke-width="1.5" rx="2"/> <text x="190" y="35" font-size="10" font-family="sans-serif" fill="#c6613f">p</text> <rect x="250" y="15" width="50" height="30" fill="none" stroke="#788c5d" stroke-width="1.5" rx="2"/> <text x="263" y="35" font-size="10" font-family="sans-serif" fill="#788c5d">n</text> <rect x="228" y="15" width="24" height="30" fill="#14140f" fill-opacity="0.08" stroke="#14140f" stroke-width="1" stroke-dasharray="3,2"/> <text x="205" y="58" font-size="8" font-family="sans-serif" fill="#c6613f">Forward (narrow)</text> <!-- Labels --> <text x="55" y="85" font-size="9" font-family="sans-serif" fill="#14140f">Forward bias &#8594; depletion narrows &#8594; current flows</text> </svg> -

Under reverse bias, the current through a diode is: -

The diode equation is I = I_0(e^(eV/nkT) - 1). At V = 0.7 V (Si, n=1, T=300K), the exponential factor is approximately: -

The barrier potential of a silicon p-n junction at room temperature is approximately: -