Carrier Recombination Properties of Low-Threshold 1.3 μm Quantum Dot Lasers on Silicon

• Published in: IEEE journal of selected topics in quantum electronics 2022-01, Vol.28 (1: Semiconductor Lasers), p.1-10
• Main Authors: Fitch, Christopher R., Baltusis, Aidas, Marko, Igor P., Jung, Daehwan, Norman, Justin C., Bowers, John E., Sweeney, Stephen J.
• Format: Article
• Language: English
• Subjects: Auger recombination; Augers; Carrier recombination; Design optimization; Devices; Engineering; Gallium arsenide; hydrostatic high pressure; Hydrostatic pressure; InAs; inhomogeneous broadening; Laser excitation; Low temperature; Optics; Physics; Pressure dependence; Pump lasers; quantum dot laser; Quantum dot lasers; Quantum dots; Radiative recombination; Room temperature; semiconductor laser; Semiconductor lasers; Silicon; Silicon substrates; Substrates; Temperature; Temperature dependence; Threshold current; Threshold currents
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2021.3101293

On-chip lasers are a key component for the realization of silicon photonics. The performance of silicon-based quantum dot (QD) devices is approaching equivalent QDs on native substrates. To drive forward design optimization we investigated the temperature and pressure dependence of intrinsic and modulation p-doped 1.3 μm InAs dot-in-well (DWELL) laser diodes on on-axis silicon substrates for comparison with devices on GaAs substrates. The silicon-based devices demonstrated low room temperature (RT) threshold current densities ( J th ) of 192 Acm −2 (538 Acm −2 ) intrinsic (p-doped). Intrinsic devices exhibited temperature stable operation from 170-200 K. Above this, J th increased more rapidly due to increased non-radiative recombination. P-doping increased the temperature at which J th (T) started to increase to 300 K with a temperature insensitive region close to RT, but with a higher J th . A strong correlation was found between the temperature dependence of gain spectrum broadening and the radiative component of threshold J rad (T) . At low temperature this is consistent with strong inhomogeneous broadening of the carrier distribution, which is more pronounced in the p-doped devices. At higher temperatures J th increases due to homogeneous thermal broadening coupled with non-radiative recombination. Hydrostatic pressure investigations indicate that while defect-related recombination dominates, radiative and Auger recombination also contribute to J th .