The resistivities of the two sides of a step graded junction

The resistivities of the two sides of a step graded junction are 5Ω-cm (p-side) and 2·5Ω-cm (n-side). The height of potential barrier V0?
(Given µp = 475 cm²/V_s and µ_n = 1500 cm²/Vs at room temperature of 300k and ni = 1·45 × 10¹⁰ atoms/cm³)

Given _p = 5Ω cm, _n = 2·5Ω cm, µ_p = 475 cm² /Vs, µ_n = 1500 cm² /V–s, n_i = 1·45 × 10¹⁰ atoms/cm³
We know that _n = nq µ_n

1	nq µ_n
n

= 1·667 × 10¹⁵ atoms/cm³

and _p N_A =	1
	_p qµ_p

=	1
	5 × 1·6 × 10^–19 × 475

= 2·631 × 10¹⁵ atoms/cm³

Now, V₀ = V_T l_n	N_AN_D	= 25 x 10^-3
	n_i²

I_n =	(1.667 x 10¹⁵ x 2.631 x 10¹⁵)
	(1·45 × 10¹⁰)²

593·4 mV
Hence alternative (B) is the correct choice.