Broadband Light Emission from Chirped Multiple InAs Quantum Dot Structure

Broadband light emission is obtained from a chirped multiple InAs/InGaAs/GaAs quantum dot (QD) structure. The thickness of the InGaAs strain-reducing layer (SRL) is used as the tuning parameter to adjust the light emission property of each QD layer in the chirped structure. It is shown from the photoluminescence (PL) measurement that the SRL thickness has a strong influence on the PL peak position, linewidth, and intensity. By constructing the chirped QD structure comprising five groups of QD layers with different SRL thicknesses, a broadband electroluminescence emission with the full width at half maximum of 202 nm is realized, indicating the feasibility of chirped multiple InAs QD layers on broadening the emission spectrum.