An analytical expression for the built-in potential in a heavily doped high-low (p+-p) junction has been derived. The magnitude of built-in potential at different values of dopant density is estimated numerically. Band gap narrowing, carrier degeneracy, dopant density-dependent dielectric constant and also effects of carrier lifetime across the junction are considered in the analysis. The variation of surface recombination velocity with dopant density has been shown graphically through numerical analysis, where the variation of built-in potentials is incorporated.