An abrupt silicon pn junction with a cross-sectional area of 10-4 cm² has the following properties at T=300K:

n region p region
ND = 10¹⁷cm⁻³ NA = 5x 10¹⁵cm⁻³
Tp = 10⁻⁷s Tn = 10⁻⁶
μn = 850 cm²/V.s μn = 1250 cm²/V.s
μp = 320 cm²/V.s μp = 420 cm²/V:s

Determine the ratio of hole current to total current at the space charge edge Xn.