Determine the number of density of donor atoms which have to be added to an intrinsic germanium semiconductor to produce an N-type semi-conductor of conductivity 6.4 `Omega cm^(-1)` . Given that mobility of electron in N-type Ge is 4000 `cm^(2)//Vs`. Neglect the contribution of holes. to conductivity.

Mobility of electron in N-type Ge is 5000 cm^(2)//"volt" sec and conductivity 5 "mho/cm" . If effect of holes is negligible then impurity concentration will be

Mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for an n-type semiconuctor, the density of electrons is 10^(19)m^(-3) and their mobility is 1.6m^(2)//(V.s) then the resistivity of the semiconductor (since it is an n-type semiconductor contribution of holes is ignored) is close to :

If N_(A) is number density of acceptor atoms added and N_(D) is number density of donor atoms added to a semiconductor, n_(e) and n_(h) are the number density of electrons and holes in it, then

The intrinsic conductivity of germanium at 27^(@)C is 2.13ohm^(-1)*m^(-1) , the mobilities of electrons and holes are 0.38 and 0.18m^(2)//(V*s) , respectively. Compute the carrier densities and the Hall coefficient.

In an intrinsic (pure) semiconductor, the number of conduction electrons is 8xx10^(19) per cubic meter. Find the total number of current carriers (electrons & holes ) in a same semiconductor of size 1 cm x 1 cm x 1mm.

In an intrinsic (pure) semiconductor, the number of conduction electrons is 7xx10^(19) per cubic meter. Find the total number of current carriers (electrons & holes ) in a same semiconductor of size 1 cm x 1 cm x 1mm.

A particular semiconductor in equilibrium has 1xx10^(16)cm^(-3) donor atoms, 1.1xx10^(17)cm^(-3) acceptor atoms. If the intrinsic carrier density (n_(i)) of the semiconductor is 10^(12)cm^(-3) , then the electron density in it will be

A dence collection of equal number of electrona and positive ions is called netural plasma. Certain solids contianing fixed positive ions surroundedby free electrons can be treated as neytral plasma. Let 'N' be the numbrer density of free electrons, each of mass ' m '. When the elctrons are subjected to an eletric field, they are displaced relatively away from the heavy positive ions. if the electric field becomes zero, the electrons begin to oscillate about the positive ions with a natural angular frequency ' omega_(P)' which is called the plasma frequency. to sustain the oscillations, a time varying electric field needs to be applied that has an angular frequrncy omega , where a part of the energy is absorbed and a part of it is reflected. As omega approaches omega_(p) all the free electrons are set to resonance together and all the energy is reflected. this is the explaination of high reflectivity of metals. (2) Estimate the wavelength at which plasma reflection will occur for a metal having the density of electrons N~~ 4 xx 10^(27)m^(-3) . Taking epsilon_(0) = 10^(11) and mass m~~ 10^(-30) , where these quantities are in proper SI units.

Mobilities of electorns and holes in a sample of intrinsic germanium at room temperature are 0.54m^(2)V^(-1)s^(-1) and 0.18m^(2)V^(-1)s^(-1) respectively. If the electron and hole densities are equal to 3.6xx10^(19)m^(-3) calculate the germanium conductivity.

In a pure semiconductor, the number of conduction electron is 6xx10^(19) per cubic meter. How many holes are there in a sample of size 1 cm x 2 cm x 2mm ?