Electronics Engineering

Space Charge Region at a Junction: As explained already, the interface separating the N and P-regions is called the metallurgical junction. Let us consider a step junction in which the doping concentration is uniform in each region but there is an abrupt change in doping at the junction. Initially, at the metallurgical junction, there is […]

Charge Neutrality Equation in Semiconductor: The semiconductor crystal is electrically neutral under thermal equilibrium conditions. The electrons are distributed among the different energy states, producing both negative and positive charges but the net charge density is zero. This charge neutrality condition is used for determination of the thermal-equilibrium electron and the hole concentrations as a

Equilibrium Conditions in Semiconductor Physics: The electron and hole concentrations, under thermal Equilibrium Conditions can be found by knowing the position of the Fermi energy EF with respect to the bottom of the conduction band energy EC and top of valence band energy EV. As discussed already, in case of an intrinsic semiconductor, the Fermi

Basic Structure of PN Junction in Semiconductor: Most semiconductor devices employ one or more P-N junctions. The P-N junction is the control element for the performance of all semiconductor devices such as rectifiers, amplifiers, switching devices, linear and digital integrated circuits. The PN Junction in Semiconductor is produced by placing a layer of P-type semiconductor

What is Hall Effect in Semiconductor?: When a specimen (metal or semiconductor) is placed in a transverse magnetic field and a direct current is passed through it, then an electric field is induced across its edges in the perpendicular direction of current as well as magnetic field. This phenomenon is called the Hall effect in

Continuity Equation in Semiconductor: The Continuity Equation in Semiconductor states a condition of dynamic equilibrium for the concentration of mobile carriers in any elementary volume of the semiconductor. In Fig. 6.21 we have seen that on disturbing the equilibrium concentrations of carriers (electrons and holes) in a semiconductor, the concentrations of holes or electrons vary

Carrier Lifetime in Semiconductor: As already explained, in an extrinsic semiconductor the number of holes is equal to the number of free electrons. Due to thermal agitation, new electron-hole pairs are continually generated while other electron-hole pairs disappear as a result of recombination i.e., free electrons falling into empty covalent bonds. On an average, a

Fermi Level in Extrinsic Semiconductor: The equation for f(E) specifying the fraction of all states at energy E (electron volts) occupied under conditions of thermal equilibrium is called the Fermi-Dirac probability function and is given as where k is Boltzmann constant in eV/K, T is temperature in K and EF is the Fermi level or

Carrier Concentration in Intrinsic Semiconductor: For determination of the conductivity of a semiconductor, it is essential to know the Carrier Concentration in Intrinsic Semiconductor of free electrons in conduction band and concentration of holes in valence band. Number of Electrons in the Conduction Band: The product of the number of existing states at any energy

Explain Conduction in Intrinsic Semiconductors: Explain Conduction in Intrinsic Semiconductors – As already explained, conduction through a semiconductor is due to two mechanisms viz. drift and diffusion. The movement of charge carriers (electrons and holes) under the influence of an applied electric field E is termed as the drift current. The conductivity of σe of