Modulation of carrier dynamics and threshold characteristics in 1.3-μm quantum dot photonic crystal nanocavity lasers

• An all-pathway rate equation model is investigated in nanocavity.
• The carrier occupation in QDs is modulated by quality factor.
• The threshold current is improved nonlinearly by quality factor.
• The influence of quality factor on carrier injection efficiency is discussed.

A self-consistent all-pathway quantum dot (QD) rate equation model, in which all possible relaxation pathways are considered, is used to investigate the influence of quality (Q) factor on the carrier dynamics of 1.3-μm InAs/GaAs QD photonic crystal (PhC) nanolasers. It is found that Q factor not only affects the photon lifetime, but also modulates the carrier occupation in QDs. About three times increases of carrier injection efficiency in QD ground state can be realized in nanocavity with high Q factor. However, it also reveals that over 90% improvement of threshold current happens when Q factor increases from 2000 to 7000, which means it might be not necessary to pursuit for ultrahigh Q factor for the purpose of low threshold current.