Semiconductor Devices And Logic Gates

When the input voltage exceeds the Zener breakdown voltage , the Zener diode enters breakdown mode and maintains a constant voltage across itself, which is . This characteristic allows the Zener diode to regulate the output voltage.In this circuit, the breakdown voltage of the Zener diode is given as 4 V . Therefore, regardless of the value of (as long as is greater than ), the voltage across the Zener diode remains at 4 V .Using Kirchhoff's Voltage Law (KVL) around the loop, we have:$ $

In an intrinsic semiconductor, the intrinsic electron concentration and hole concentration are equal, i.e., .When the semiconductor is doped with trivalent impurities (which are known as acceptors), these impurities accept electrons, creating more holes. This type of doping is called p-type doping.Trivalent impurities (acceptors): These impurities have three valence electrons, which means they can accept an electron to form a complete bond with the silicon atoms. This acceptance of electrons leaves behind holes.Upon doping with trivalent impurities:The hole concentration will increase significantly because the acceptors create additional holes.The electron concentration will decrease because the acceptors capture electrons, thereby reducing the number of free electrons.Therefore, in a Si-based semiconductor doped with trivalent impurities, the hole concentration will be greater than the electron concentration . Thus, .Note: The intrinsic electron concentration and hole concentration in a semiconductor are highly dependent on temperature. As temperature increases, both and increase.