GATE 2026 EC – Question 64

Consider that the concentration of electrons in a semiconductor bar varies linearly from $2\times10^{17}$ cm$^{-3}$ at $x=1$ μm to $1\times10^{16}$ cm$^{-3}$ at $x=4$ μm along the $x$-direction. Assume that the concentration of electrons is not varying along other directions (that is along $y$- and $z$-directions). [Given: the mobility of electron is 1400 cm$^2$V$^{-1}$s$^{-1}$, thermal voltage is 25 mV and electronic charge is $1.6\times10^{-19}$ Coulomb.] The density of electron diffusion current (in A/mm$^2$) is ________. (rounded off to two decimal places)