The electron concentration in a sample of uniformly doped n-type silicon at 300^oK varies linearly from $$10^{17}/cm^3$$ at x = 0 to $$6\times10^{16}/cm^3$$ at x = 2 $$\mu m$$. Assume a situation that electrons are supplied to keep this concentration gradient constant with time.If electronic charge is $$1.6\times10^{-19}\;coulomb$$ and the diffusion constant $$D_n=3\;cm^2/s$$, the current density in the silicon, if no electric field is present is

An n-type silicon bar 0.1 cm long and $$100\;\mu m^2$$ in cross-sectional area has a majority carrier concentration of $$5\times10^{20}/m^3$$ and the carrier mobility is $$0.13\;\;m^2/v-s\;$$ at 300^oK. if the charge of an electron is 1.6×10^-19 coulomb, then the resistance of the bar is

A semiconductor is irradiated with light such that carriers are uniformly generated throughout its volume. The semiconductor is n-type with $$N_D=10^{19}/cm^3$$. If the excess electron concentration in the steady state id $$\triangle n=10^{15}/cm^3$$ and if $$\tau_p=10\;\mu\;sec$$ [minority carrier life time] the generation rate due to irradiation

A silicon sample is uniformly doped with 10¹⁶ phosphorous atoms/cm³ and 2 ×10¹⁶ boron atoms/cm³. If all the dopants are fully ionized, the material is