Electroluminescence Studies on Long Wavelength Indium Arsenide Quantum Dot Microcavities Grown on Gallium Arsenide Thesis

A comprehensive study of the electroluminescence of four longwavelength microcavity devices with InAs/GaInAs quantum dot active regions emitting near 1.3 μm was conducted. The four molecular beam epitaxial grown samples with AlAs oxide aperture confinement layers were fabricated, characterized, and optically modeled. Optical power transmission of the samples was modeled using Matlab and compared with actual measured transmission data. Resonant cavity light emitting diodes (RCLEDs) and three 1.3 μm vertical cavity surface emitting laser (VCSEL) samples were fabricated and electro-optically characterized over a range of injection currents and temperatures. An intra-cavity contacted VCSEL photolithographic mask set was designed and created for this study. Devices achieved continuous wave room temperature lasing at 1.28μm with an output power of more than 3 mW, a threshold current of 2.3 mA, and a slope efficiency of 10.3 W/A. The characteristic temperature was 49.4 K and the wall plug efficiency was a maximum of over 36%. This was made possible by the optical and current confinement of the Al2O3 apertures that provided a beneficial impact on the device output efficiency. The FWHM of the quantum dot active region was 27 meV with a separation of 62 eV between the peak of the ground state and excited state transitions. The minimum threshold current was observed at a chuck temperature of -10°C, and did not occur at the point where the peak of the gain curve and cavity resonance were matched (10°C). The cavity resonance of the VCSEL was tuned at a wavelength too short for the peak wavelength of the active region gain curve limiting the temperature at which the VCSELs produced lasing to about room temperature.