Influence of localization on the optical properties of ordered(Al0.5Ga0.5)

Barrier-induced carrier localization effects in ordered/disordered/ordered quaternary quantum wells grown onGaAssubstrates

“…At this point, experimental data may point to ordering influence on the QW emission, since for thicker layers the HE band ͑thus the bulk spectra͒ is recovered. [7][8][9] Before we could identify the physical mechanism of the anomalous PL behavior as a function of excitation power ͑Fig. 2͒, other alternatives must be explored.…”

“…[5][6][7] Anomalous photoluminescence ͑PL͒ emission bands from partially ordered ternary and quaternary alloy layers grown on GaAs substrates have been previously reported. [6][7][8][9] The emission characteristics of these bands are strongly dependent on the growth conditions and substrate orientation. [8][9][10] In partially ordered alloys an inhomogeneous distribution of ordered domains with different sizes and ordering degrees gives rise to potential fluctuations in the real space.…”

“…[6][7][8][9] The emission characteristics of these bands are strongly dependent on the growth conditions and substrate orientation. [8][9][10] In partially ordered alloys an inhomogeneous distribution of ordered domains with different sizes and ordering degrees gives rise to potential fluctuations in the real space. 9 At low temperatures photo-generated carriers tend to localize in the minima of these potential fluctuation.…”

“…[8][9][10] In partially ordered alloys an inhomogeneous distribution of ordered domains with different sizes and ordering degrees gives rise to potential fluctuations in the real space. 9 At low temperatures photo-generated carriers tend to localize in the minima of these potential fluctuation. The effectiveness of the carrier localization process depends on the ratio between the length scale of the potential fluctuations and the excitonic Bohr radius.…”

“…The effectiveness of the carrier localization process depends on the ratio between the length scale of the potential fluctuations and the excitonic Bohr radius. 9 The low-temperature PL characteristics of partially ordered alloys is frequently described by a broad low-energy emission, with respect to the absorption edge, with long radiative lifetimes, anomalous peak position dependence with temperature and strong blue shift with power excitation levels. 8 The coexistence of ordering and phase alloy separation effects modifies even further the band structure of quaternary heterostructures grown on GaAs substrates.…”