Optical properties of InAs/In0.15Ga0.85As quantum dots-in-a-well studied by piezomodulated reflectance spectroscopy

Piezomodulated reflectance (PzR) spectroscopy has been used to study the InAs/In0.15Ga0.85As quantum dots-in-a-well (DWELL) samples in the temperature range of 70-300 K. The optical transitions from ground state to excited states in InAs DWELL were observed. The heavy- and light-hole transitions from the hybrid quantum well (HQW) were identified by combining the one-dimensional effective mass approximation (EMA) with the selected modulation effect in PzR spectrum. A remarkable red shift of the ground state has been observed in the InAs DWELL with optimized growth of In0.15Ga0.85As quantum well layers. Cooling both DWELL samples produces an abnormal broadening of the QD transitions in PzR spectra.