Defect-related luminescence in InAlAs on InP grown by molecular beam epitaxy

Abstract

The photoluminescence (PL) of InAlAs grown on InP has been studied in a wide range of temperatures and excitation intensities. A novel emission ascribed to the presence of defects has been found by about 120-180 meV below the near band edge (NBE) line. The novel wide PL band is observed in the spectra only in a limited range of temperatures of 50-160 K, and is seen neither at liquid helium nor at room temperatures. The analysis of the PL behaviour with sample temperature and excitation power together with non-stationary PL kinetics allows us to conclude that both the NBE PL and the novel PL band are controlled by transitions via states of band tails formed due to alloy disorder in these films. The NBE PL is caused by recombination of carriers in the band tails, while deep levels related to defects and located in the same regions as the deepest band tail states are supposedly involved in the defect-related PL transitions. We demonstrate that no defect-related PL is found in the spectra if quasi-stoichiometric growth conditions were used during film growth, which resulted in a PL efficiency by about 1-2 orders of magnitude greater than that of samples grown under more common As-rich conditions.

Optimization of MBE Growth Conditions of In0.52Al0.48As Waveguide Layers for InGaAs/InAlAs/InP Quantum Cascade Lasers

“…Three groups of transitions are present in the low-temperature spectra. The lines peaked at ~1.51 eV–1.55 eV can be attributed to near band edge (NBE) luminescence of the InAlAs layer [24,25]. Energy spread of their positions results from differences in alloy’s composition, which were indeed confirmed by X-ray diffraction.…”

The Variation of Schottky Barrier Height Induced by the Phase Separation of InAlAs Layers on InP HEMT Devices

“…In the HT-InAlAs sample, three peaks located at P 1 = 1.48 eV, P 2 = 1.36 eV, and P 3 = 1.25 eV are observed. We estimated that those PL peaks are originated from PL transitions in the In 0.51 Al 0.49 As (P 1 ), InP (P 2 ), and In 0.52 Al 0.48 As/InP interface (P 3 ), respectively [16,17]. Generally, the PL transitions for In x Al 1−x As layers are related to the bandgap energy which varies with the In composition x.…”

Phase Separation Induced Schottky Barrier Height Change in InAlAs/InP Heterostructure-based HEMT Devices

“…We estimated that those PL peaks are originated from PL transitions in the In 0.51 Al 0.49 As (P1), InP (P2), and In0.52Al0.48As/InP interface (P3), respectively. 16,17 Generally, the PL transitions for InxAl1-xAs layers are related to the bandgap energy which varies with In composition x. When In composition x varies in the range 0.51 ∼ 0.52, the bandgap energy measured by PL is in the range 1.46 ∼ 1.48 eV at room temperature.…”