Internal photoemission and band discontinuities at Ga0.47In0.53As-InP heterojunctions

Internal photoemission has been observed in the spectral response of specially designed Ga0.47In0.53As-InP p+N− heterojunction photodiodes. Power-law fits to the internal photoemission as a function of photon energy allow precise determination of threshold energies from which the conduction-band discontinuity is easily and accurately deduced to be ΔEc=203±15 meV at room temperature. These measurements have been performed at temperatures from 135 to 297 K. The temperature dependence of ΔEc is described by ∂(ΔEc)/∂T=−0.2±0.1 meV/K.