Photoconductivity and Hall measurements in InP are presented for pressures up to 4 GPa using a diamond anvil cell. The application of pressure increases the direct energy band gap (E0
), as seen by the shift of the photoconductivity edge to lower wavelength with increasing pressure. Hall measurements show a decrease in the electron mobility (μe
) with pressure, due mainly to an increasing effective mass (m@B|e
). Analysis of the pressure dependence of μe
shows that polar optical scattering is the dominant mechanism.