Analysis of redshift in InAs/InGaAs quantum dot with Fourier-transform based k·p method

We present a theoretical study on mechanism of redshift in InAs/In_xGa_(1-x)As quantum dots, of which redshift is realized via controlling In composition x and lower confining layer thickness t to ease up the enlargement of band gap due to strain. Introducing In component in the confining layer material leads to significant redshift but thermal quenching due to waning band discontinuity, therefore proper In composition x and thicker lower confining layer are adopted to balance this contradictory. Both the band-edge profiles and ground-state energies indicate that the adjustable ability of strain on redshift decreases as increase of In component. In component modified band edges of confining layer material may also make a contribution on redshift. The most proper range of In composition for obvious redshift is 0≤ x ≤0.33 to avoid size fluctuations and small thermal quenching luminescense.