Semiconductor Physics

Explain Steady State Conditions in Semiconductor: Explain Steady State Conditions in Semiconductor – When the P-N junction is forward biased, current flows quite freely P to N in a P-N junction, as discussed in Fig. 6.28. But when the P-N junction is reverse biased, there is virtually no flow of current. This asymmetry of the […]

Metal Semiconductor Junctions: Metal semiconductor junctions are very common in all semiconductor devices and are very important. Depending upon the doping concentration, materials, and the characteristics of the interface, the metal semiconductor junctions can act as either an ohmic contact or as a Schottky barrier. Structure of Metal Semiconductor Junctions: A metal-semiconductor junction, as its

Zero bias PN junction: Zero bias PN junction – Here we will examine the properties of the step junction in thermal equilibrium, where no currents exist and no external excitation is applied. We will determine built-in potential barrier through the depletion or space-charge region, electric field and width of the space-charge region. Built-in Potential Barrier:

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