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Description
We demonstrate digital alloy (DA) Al0.4Ga0.07In0.53As PIN structures nearly lattice-matched to InP substrates. Ternary and quaternary alloys on InP substrates have suffered from phase separation during the growth. The thin AlInAs and InGaAs layers were periodically stacked as a superlattice. Using photoluminescence (PL) spectroscopy, we have studied the thickness effect in AlGaInAs PIN structures. The thickness of each quaternary layer was 4ML, 6ML, and 8ML, respectively. At a low-temperature PL, the emission centers show 1.379 eV, 1.378 eV, 1.362 eV, respectively. The redshift was observed with increasing thickness. This redshift shows the energy state in superlattice layers due to an increase in barrier heights. Especially1, the 6 ML PL spectra show asymmetry shapes at low temperatures. These PL shapes show that the 6ML interface has two different emission centers.
