1.3micron quantum dot lasers and superluminescent light emitting diodes

The work described in this thesis involves the development of gallium arsenide based quantum dot lasers and superluminescent light emitting diodes (SLEDs) emitting around 1.3 pm. Initially, the improvement in overall temperature characteristics of a 5 DWELL 1.3 pm quantum dot laser is described through a change in the fabricated device design incorporating a shallow ridge etch and selective gold electroplating. This improved fabrication technique allowed higher temperature ground state operation of the laser and an improvement of 10K in the characteristics temperature at a temperature range higher than 60°C. Later a novel method to broaden the emission spectrum of a SLED by incorporating different amounts of indium in different wells of a DWELL structure is proposed and described. For this device 85nm broad emission spectrum is obtained along with 2.5mW of CW output power at room temperature. Further modification of this structure resulted in a SLED with >8mW CW output power and a 95nm wide, flat emission spectrum at room temperature. In the last part of this thesis a new growth mechanism is described to improve the overall performance of lasers, SLEDs and mesa diodes. For the laser structures lower threshold current density, higher efficiency and lower transparency current densities are observed while the SLEDs emitted >40mW CW output power at room temperature which linearly increased with drive current. Also the mesa diodes exhibited lower reverse leakage current and higher breakdown voltages.