(a) UEIPL spectra of the InAs/GaAs QD sample subjected to femtosecond laser excitation at different pulse powers. The sample was mounted on the liquid nitrogen cooled cryostat with a nominal temperature of 77 K. (b) PL spectra of the sample at the excitation powers of 2 and , respectively. The PL intensity at is magnified by ten times and the whole curve is then shifted down along the vertical direction for clarity.
Peak energies of D1, DD, and D3 as a result of excitation power.
(a) Peak energies of WLhh, WLlh, and GaAs as a result of excitation power. (b) Excitation power dependence of FWHM for the WLhh and WLlh features, along with the results of power law fitting.
(a) Lattice temperature derived from the emission peaks of D1, DD, D3, WLhh, WLlh, and GaAs, respectively. Dots represent the peak energy at different excitation power, while the dot-dashed lines are fitted results according to Varshni’s formula. (b) Relationship between the laser excitation power and lattice temperature.
(a) PL intensity as a function of lattice temperature for D1, DD, D3, WLhh, and WLlh. (b) Normalized PL intensity as a function of lattice temperature for D1. The dot-dashed lines are fitted curve for D1. The thermal activation energy is derived as approximately 290 meV which is close to the energy difference between the D1 and WL emission peaks.
FWHM as a function of lattice temperature for D1, DD, D3, WLhh, and WLlh.
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