AlyGa1-yAs Bound GazIn1-zP Strain Compensation for Optical Enhancement of In0.07GaAs/GaAs1-xPx 940-nm Light-Emitting Diodes

The use of an AlxGa1-xAs bound GazIn1-zP strain compensation structure for optimum strain in latticed mismatched In0.07GaAs/GaAsP0.06 multiple quantum wells (MQWs) and its effect on the output power of an infrared light-emitting diode at 940-nm were investigated. A Ga0.53InP tensile strain structure, which effectively compensate excessive compressive strain in the In0.07GaAs/GaAsP0.06 MQWs, was inserted between a quantum well and a quantum barrier. The Al0.2GaAs material was used as both a growth buffer and a balancing barrier for In0.07GaAs/AlxGa1-x As-bound Ga0.53InP/GaAsP0.06 MQWs. From photoluminescence (PL) measurements and X-ray diffraction (XRD) rocking curves, we verified that the Ga0.53InP tensile strain barrier could effectively compensate the compressive strain of the In0.07GaAs/GaAsP0.06 MQWs. In addition, a further increase in the PL intensity from the In0.07GaAs/AlyGa1-yAs-bound Ga0.53InP/GaAsP0.06 MQWs was found after having adjusted the Al0.2GaAs strain tuning barrier. This result was significantly supported by the stable balance of the energy bandgap structure in the developed MQWs. From fabricated IR-LEDs chips, the LED with an In0.07GaAs/GaAsP0.06 MQW employing the Al0.2GaAs-bound Ga0.53InP strain compensation structure displayed a 48% higher light output power as compared with a conventional LED. These results suggest that the use of an Al0.2GaAs-bound Ga0.53InP strain compensation structure effectively improved both the unbalanced strain and the unbalanced energy bandgap of lattice-mismatched In0.07GaAs/GaAsP0.06 MQWs for 940-nm IR-LEDs.