An In0.49Ga0.51P∕In0.49(Ga0.6Al0.4)0.51P multi-quantum-well (MQW) structure grown by molecular beam epitaxy using a digital alloy method was parametrically investigated by photoluminescence (PL) measurement performed in a temperature range of 10–290K. The PL peak energies did not change with increasing temperature up to 60K, while the PL peak energy monotonously decreased with increasing temperature beyond 60K. From the curve fit of the linewidth full width at half maximum of the PL peak, it was observed that the homogeneous broadening of In0.49Ga0.51P∕In0.49(Ga0.6Al0.4)0.51P MQW with digital alloy barriers due to scattering by longitudinal optical phonons was smaller than that of InGaAs∕InGaAlAs MQW with digital alloy barriers. This is in accordance with the existence of a relatively weak phonon-related PL peak in the PL spectrum of InGaAlP digital alloy, as compared with InGaAlAs digital alloy. The fit of the integrated PL intensity shows the occurrence of a nonradiative recombination process with an activation energy E1=24.4meV up to 60K. On the other hand, the process of nonradiative recombination with an activation energy E2=109meV occurred above 60K, which is in good agreement with one-half of the calculated total confinement energy ΔE of the electron-hole pair in the quantum well (∼108meV). The In0.49Ga0.51P∕In0.49(Ga0.6Al0.4)0.51P MQW structure with digital alloy barriers has larger activation energy (E2=109meV) than In0.49Ga0.51P∕In0.49(Ga0.6Al0.4)0.51P MQW (E2=90meV) with analog alloy barriers. Therefore, the thermal emission of carriers into the barrier can be reduced at temperatures above 60K due to the high effective barrier height.

The optical properties of quantum wires (QWRs) grown using lateral composition modulation (LCM) were studied by photoluminescence (PL) measurement as a function cryostat temperature (Tcr). 3 stacked arrays of QWRs were formed by sequential growth of ∼ 180 Å-thick LCM layers (lateral period: ∼ 90 Å) induced by (InP)1/(GaP)1 short-period superlattices, and 200 Å-thick InGaP spacers at the growth temperature of 490 °C. The formation of QWRs was confirmed by a transmission electron microscopy measurement. By the analysis of the dependence of PL intensity and peak energy of the QWRs on Tcr, the origin of higher energy peak (H) and lower energy peak (L) were investigated. While behavior of the H peak is similar to that of an ordered InGaP, the L peak shows the insensitivity of PL peak energy to Tcr. This is attributed to compensation of the bandgap by competition of strain in the QWR region and indicates the L peak is related to the QWRs. Strong dependence of the L peak on the position of polarizer also supports this. Additionally, the PL peak intensity of the L peak has the maximum value not at the lowest Tcr (10 K) but at 50 K, while the H peak decrease continuously as T increases. We introduced the idea of compensation of the thermal expansion coefficient to explain this phenomenon.