A comparison of lattice-matched GaInNAs and metamorphic InGaAs photodetector devices

The dilute-nitride GaInNAs shows great promise in becoming the next choice for 1 eV photodetector and multi-junction photovoltaic applications due to the ability for it to be grown lattice-matched on GaAs substrates. This paper will present results from high-power photodetector devices fabricated from high-quality thick GaInNAs and metamorphic InGaAs materials grown by MBE. The internal quantum efficiency of rear-illuminated PIN photodiodes with thick GaInNAs films as the intrinsic region (roughly 62% at 1064 mn) is somewhat lower than comparable metamorphic InGaAs devices (roughly 75% at 1064 mn). However, the dark current density of the GaInNAs devices is also somewhat lower (roughly 3 mu A/cm(2) at 2x 10(4) V/cm bias) than the InGaAs devices (roughly 20 mu A/cm(2) at 2x10(4) V/cm bias), while the breakdown voltages (beyond -20 V) are comparable. Materials characterization of each structure, including x-ray diffraction and room-temperature as well as temperature-dependent photoluminescence studies will be presented in order to explain the characteristics observed in the devices composed of the two different material systems.