Suppressing non-radiative generation and recombination in LEDs, PVs, and photodiode detectors via inhomogeneous doping around the depletion region co-located with a heterojunction

We present a design principle for photonically-active double-heterojunction (DHJ) diodes that utilizes spatial control over the distribution of dopant impurities in the growth direction to suppress non-radiative Shockley-Read-Hall (SRH) carrier generation and recombination processes. These non-radiative processes constitute major parasitics in numerous devices, including light-emitting diodes (LEDs), photovoltaics (PVs), and photo-diode detectors (PDs). The design principle is general to all diodes with carrier-confining heterojunctions and is agnostic to material system. As a result, devices based on semiconductors in Group IV (e.g. SiGe), III-V (e.g. GaN, AlGaAs, GaInAsP, GaInAsSb), II-VI (e.g. MgZnCdTe, ZnCdSeS), and others can theoretically benefit from it. To illustrate the principle, here we will model LEDs, PVs, and PDs in the InP-lattice-matched GaInAsP material system. We show that LEDs’ Internal Quantum Efficiency (IQE) is raised, with a major impact at low forward bias voltages. The modeling presented here shows that, because thermophotonic refrigerator LEDs operate at these voltages, the design principle could prove to be a major step toward realizing the Kelvinscale and larger temperature reductions that have remained experimentally elusive to date. Next, we show that redesigned PVs exhibit higher open-circuit voltage and efficiency, with significant improvement in cells with the high defect densities typical of lattice mismatched III-V cells grown on inexpensive Silicon substrates. Finally, we show that PDs exhibit improvements in dark current during reverse bias operation and shunt resistance during photovoltaic operation, quantities that can impact the noise floor of receivers in optical communication systems and thus the overall power consumption of photonic links.