1
GATE ECE 2015 Set 2
Numerical
+1
-0
A piece of silicon is doped uniformly with phosphorous with a doping concentration of $$10^{16}/cm^2$$. The expected value of mobility versus doping concentration for silicon assuming full dopant ionization is shown below. The charge of an electron is $$1.6\;\times\;10^{-19}\;C$$. The conductivity (in S cm-1) of the silicon sample at 300 K is _________________.
2
GATE ECE 2015 Set 1
Numerical
+1
-0
A silicon sample is uniformly doped with donor type impurities with a concentration of $$10^{16}/cm^3$$.The electron and hole mobilities in the sample are $$1200\;cm^2/V-s$$ and $$400\;cm^2/V-s$$ respectively. Assume complete ionization of impurities. The charge of an electron is $$1.6\;\times\;10^{-19}\;C$$.The resistivity of the sample $$\left(in\;\Omega-cm\right)$$ is _____________.
3
GATE ECE 2014 Set 4
+1
-0.3
In the figure ln(ρi) is plotted as a function of 1/T, where ρi the intrinsic resistivity of silicon, T is is the temperature, and the plot is almost linear.

The slope of the line can be used to estimate

A
Band gap energy of silicon (Eg)
B
Sum of electron and hole mobility in silicon $$\left(\mu_n+\mu_p\right)$$
C
Reciprocal of the sum of electron and hole mobility in silicon $$\left(\mu_n+\mu_p\right)^{-1}$$
D
Intrinsic carrier concentration of silicon (ni)
4
GATE ECE 2014 Set 4
Numerical
+1
-0
The cut-off wavelength (in µm) of light that can be used for intrinsic excitation of a semiconductor material of bandgap Eg= 1.1 eV is ________.