The total current in a semiconductor is constant and is composed of electron drift current and hole diffusion current. The electron concentration is constant and is equal to 10^17 cm^-3. The hole concentration is given by p(x)=5x10^15 exp(-x/L) cm^-3 ; (x>=0) where L=10um. The hole diffusion coefficient is Dp=12 cm^2 / s and the electron mobility is Un=1000 cm^2 / V-s. The total current density is J = 5A/cm^2. Calculate (a) the hole diffusion current density versus x, (b) the electron current density versus x, and (c) the electric field versus x.