A pn-junction is uniformly doped and has dopant concentration of NA = 4 x1016 cm-3 in the pregion at 300K.

Hi, i need help with this question.A pn-junction is uniformly doped and has dopant concentration of NA = 4 x1016 cm-3 in the pregionat 300K. At zero bias, 20% of the total space charge region (W) is extended in the pregion.Calculate Vbi, ND, W, xn and xp. Given that ni = 1.8 x 106 cm-3 and ε=1.16 x 10-12 F/cm. Hint: Ndxn=Naxp