Holes are being steadily injected into a region of n-type silicon (connected to other devices, the details of which are not important for this question). in the steady state, the excess-hole concentration profile shown in fig. p3.10 is established in the n-type silicon region. here "excess" means over and above the thermal-equilibrium concentration (in the absence of hole injection), denoted pn0. if nd = 1016/cm3, ni =1.5×1010/cm3, dp =12 cm2/s, and w =50 nm, find the density of the current that will flow in the x direction.