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Electron And Hole Equilibrium Concentrations 24 February 2014. Return and discuss Quiz 2 Chapter 4 Topics-Two burning questions: What is the density of states in the conduction and valence bands? How do you find an exact position of the Fermi Level?.

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## Electron And Hole Equilibrium Concentrations 24 February 2014

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**Electron And Hole Equilibrium Concentrations24 February 2014**• Return and discuss Quiz 2 • Chapter 4 Topics-Two burning questions: • What is the density of states in the conduction and valence bands? • How do you find an exact position of the Fermi Level?**Concentration of Electrons at Equilibrium**Thermal-equilibrium concentration of electrons (#/cm3) in the conduction band Assume that EF is within the energy bandgap and there is So for energy levels in the conduction band (kT ≈ 25.9 meV for T=300K). So for energy levels in the conduction band Page 87 Text, Equation 3.69**Concentration of Electrons at Equilibrium**Define effective density of states in the conduction band 5**Concentration of Holes at Equilibrium**Thermal-equilibrium concentration of holes (#/m3) in the conduction band Assume that EF is within the energy bandgap and there is So for energy levels in the conduction band then for energy levels in the conduction band 7**Concentration of Holes at Equilibrium**Define effective density of states in the valence band 8**Carrier Concentrations in Intrinsic Semiconductors**For an intrinsic semiconductor, the concentration of electrons in the conduction band is equal to the concentration of holes in the valence band is the Fermi-level for the intrinsic semiconductor, i.e., intrinsic Fermi-level For a given semiconductor, at constant temperature, ni isconstant 10**Electron and Hole Concentrations in Extrinsic Semiconductor**Summary For both undoped material and doped material under equilibrium condition 14**Position of Fermi Energy in Extrinsic Semiconductors**Position of Fermi-level: 15

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