A junction is made between $p^{-Si}$ with doping density $N_{A1}=10^{15}cm^{-3}$ and $p^{Si}$ with doping density $N_{A2}=10^{17}cm^{-3}.$ Given: Boltzmann constant $k=1.38\times 10^{-23}J\cdot K^{-1},$ electronic charge $q=1.6\times 10^{-19}C$. Assume $\text{100}\%$ acceptor ionization. At room temperature $\left ( T=300 K \right ),$ the magnitude of the built-in potential (in volts, correct to two decimal places) across this junction will be __________.