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 _________________.

An n–type silicon sample is uniformly illuminated with light which generates 10²⁰ electron hole pairs per cm³ per second. The minority carrier lifetime in the sample is 1 $$\mathrm\mu$$s.In the steady state, the hole concentration in the sample is approximately 10^x , where x is an integer. The value of x is __________________

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 _____________.

The cut-off wavelength (in µm) of light that can be used for intrinsic excitation of a semiconductor material of bandgap E_g= 1.1 eV is ________.