Intrinsic Semiconductors: Thermal Generation and Carrier Concentration

This lecture discusses intrinsic semiconductors, focusing on thermal generation processes that create free electrons and holes. The instructor explains how thermal excitation allows electrons to move from the valence band to the conduction band, generating charge carriers. The concentration of these carriers is calculated using the density of states and the Fermi-Dirac distribution. The lecture covers the occupation probability of electrons and holes, emphasizing the significance of the Fermi level in determining carrier concentrations. The instructor introduces the Boltzmann approximation for high-energy states and discusses the effective density of states for both conduction and valence bands. The relationship between the intrinsic carrier concentration and temperature is also explored, highlighting how the intrinsic carrier density varies with temperature changes. The lecture concludes with a discussion on the effective mass of charge carriers and its impact on semiconductor behavior, providing a comprehensive understanding of intrinsic semiconductor properties and their applications in electronic devices.