A bar of Gallium Arsenide (GaAs) is doped with Silicon such that the Silicon atoms occupy Gallium and Arsenic sites in the GaAs crystal. Which one of the following statement is true?

A small percentage of impurity is added to an intrinsic semiconductor at 300 K. Which one of the following statements is true for the energy band diagram shown in the following figure?

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 __________________