During formation of $\mathrm{p}-\mathrm{n}$ junction, the electrons diffuse from $\mathit{n}$-side to $\mathit{p}$-side (since, electron concentration is more in n-side compared to p-side) and the holes diffuse from $\mathrm{p}$-side to $\mathrm{n}$-side (since, hole concentration is more in p-side compared to n-side).