High speed InP/InGaAs uni-traveling-carrier photodiodes with dipole-doped InGaAs/InP absorber-collector interface

For uni-traveling carrier photodiodes (UTC-PDs) using InGaAs and InP as the absorber and collector, an abrupt heterojunction at the absorber-collector interface may induce a large degradation of current handling and microwave performance caused by the current blocking effect. In this work, UTC-PDs with dipole doping at the InGaAs/InP interface to suppress the current blocking are demonstrated. By using a dipole-doped InGaAs/InP interface, the use of InGaAsP quaternary for the interface is eliminated, which eases both material growth and device fabrication.