Home
Class 12
PHYSICS
The conductivity of an intrinsic semicon...

The conductivity of an intrinsic semiconductor depends of tempareture as`(sigma)=(sigma_0)e^(-Delta E//2kT),`where `(sigma_0)`is a constant.find the temperature at which the conductivity of an imtrinsic germanium semoconductor will be double of its value at T=300 K .Assume that the gap for germanium is 0.650 eV and remains constant as the temperature os increased.

Text Solution

Verified by Experts

Since `sigma = sigma_(0e)^((-DeltaE)/(2KT))`
Given `Delta E = 0.650eV,T = 300K`
`K = 8.62xx10^(-5)eV
according to question ,
sigma_0 sigma_(0e)^((-DeltaE)/(2KT)) = 2xxsigma_(0)e^((-DeltaE)/(2 xx K xx 300)`
`(0.650)/(2xx8.62xx10^(-5)xxT) = (-0.650)/(2xx8.62xx10^(-5)xx300)`
`(-0.650)/(2xx8.62xx10^(-5)xxT) = 6.96561xx10^(-6)`
Toking 'in'on both sides.
`We get, `(-0.650)/(2xx8.62xx10^(-5)xxT`) = -11.874525`
`rArr (1)/(T`) = (11.874525xx2xx8.62xx10^(-5))/(0.65)`
`rArr T = 317.51178 = 318K`
Promotional Banner

Similar Questions

Explore conceptually related problems

The temperature at which the root mean squres speed of a gas will be half its value at 0^(@)C is (assume the pressure remains constant)

The conductivity of a pure semiconductor is roughly proportional to T^3/2 e^(-Delta E//2kT)where (Delta)E is the band gap.The band gap for germanium is 0.74eV at 4K and 0.67eV at 300K.By what factor does the conductivity of pure germanium increase as the temperature is raised form 4K to 300K?

Let (Delta)E denote the energy gap between the valence band and the conduction band.The population of conduction electrons (and of the holes)is roughly proportional to e^(-Delta E//2kT). Find the ratio of the concentration of conduction electrons in diamond to that in silicon at room tempareture 300K. (Delta E) for silicon is 1.1 ev and for diamond is 6.0eV.How many conduction electrons are likely to be in one cubic meter of diamond ?

In an intrinsic semiconductor, the energy gap E_(g) of an intrinsic semiconductor is 1.2 eV. Its hole mobility is very much smaller than electron mobility and is indepndent of temperature. What is the ratio between conductivity at 600K and at 300K? Assume that the temperature dependence of intrinsic concentraction n_(i) is expressed as, n_(i)=n_(o)e^(-E_(g)^(')//k_B)T , where n_(o) is constant and E_(g)^(') is an energy equal to E_(g)//2 , k_(B)=8.62xx10^(-6)eVK^(-1) .

Indium antimonide has a band gap of 0.23eV between the valence and the conduction band.Find the temperature at which kT equal the band gap.

The number of electron hole pairs in a semiconductor is proportional to where for germainium triangleE=0.65 eV and the temperature increases form 280 K to 300 K find the percentage increase in the number of charge carriers

A cylindrical block of length 0.4 m and area of cross-section 0.04 m^2 is placed coaxially on a thin metal disc of mass 0.4 kg and of the same cross - section. The upper face of the cylinder is maintained at a constant temperature of 400 K and the initial temperature of the disc is 300K. if the thermal conductivity of the material of the cylinder is 10 "watt"// m-K and the specific heat of the material of the disc is 600J//kg-K , how long will it take for the temperature of the disc to increase to 350 K? Assume for purpose of calculation the thermal conductivity of the disc to be very high and the system to be thermally insulated except for the upper face of the cylinder.

In an n-type semiconductor, the fermi level lies 0.3 eV below the conduction band at 300 K. If the temperature is increased to 330K, where does the new position of the Fermi level lie?

A pure semiconductor germanium or silicon, free of every impurity is called intrinsic semiconductor. A room temperature, a pure semiconductor has a very small number of current carriers (electrons and holes). Hence, its conductivity is low. When the impurity atoms of valence five or three are doped in a pure semiconductor, we get repectively n-type ot p-type extrinsic semiconductor. In case of a doped semiconductor. n_(e)n_(h)=n_(i)^(2) , where n_(e) and n_(h) are the number density of electrons and holes respectively and n_(i) is the number density of intrinsic charge carriers in a pure semiconductor. The conductivity of extrinsic semiconductor is much higher than that of intrinsic semiconductor. (i) Name two materials to be doped in pure semiconductor of silicon to get p-type semiconductor n-type semiconductor. (ii) What do you learn from the above study?