Statement, Definition, Hall coefficient, Applications
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
The electrical conductivity measurements are not sufficient for the determination of number of charge carriers and their mobilities.
Definition, formula, derivation | Semiconductor
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
The net current flows across a semiconductor has two components: (i) Drift current (ii) Diffusion current.
Definition, Formula | Semiconductor
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
If E = 1 V/m then μ = vd Thus, mobility μ is defined as the velocity of a charge carrier per unit electrical field strength.
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
In absence of an electrical field, the free electrons (electron gas) move in all directions in a random manner.
Semiconductor
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
In extrinsic semiconductor, the resistivity decreases linearly with increase in temperature. This variation is considered under three different regions.
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
In p-type semiconductor, acceptor energy level is just above valence band (fig. 3.10).
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
The energy band diagram of n-type semiconductor is shown in figure 3.8. In n-type semiconductor, the donor level is just below conduction band.
Doping, Advantages, Types, Covalent bond, Energy band
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
In a semiconducting material, if the charge carriers originate from impurity atoms which are doped to the original material, then this type of semiconductor is known as extrinsic or impure semiconductor.
Definition, Density of Electrons, Limitations
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
The number of electrons in conduction band per unit volume of the material is called as electron concentration (n).
Charge carriers
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
Fig. 3.3 shows a two-dimensional crystal structure of germanium and energy band representation of intrinsic semiconductor at very low temperature.
Energy band Diagram, Charge carriers
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
A semiconductor in extremely pure form is known as intrinsic semiconductor. Its electrical conductivity is changed only by thermal excitation.
Subject and UNIT: Materials Science: Unit III: Semiconductors and Transport Physics
The electrons and holes in a semiconductor have energy and momentum.