  Physics based analytic equations for charge carrier profile and current
density are derived by solving the carrier transport and the continuity
equations for metal-intrinsic semiconductor-metal diodes. Using the analytic
models a physics based method is developed to extract the built-in potential
$V_{bi}$ from current density-voltage ($J$-$V$) characteristics. The proposed
method is thoroughly validated using numerical simulation results. After
verifying the applicability of the proposed theory on experimentally fabricated
organic diodes, $V_{bi}$ is extracted using the present method showing a good
agreement with the reported value.
