Microscopic View of Defect Evolution in Thermal Treated AlGaInAs Quantum Well Revealed by Spatially Resolved Cathodoluminescence

Abstract

An aluminum gallium indium arsenic (AlGaInAs) material system is indispensable as the active layer of diode lasers emitting at 1310 or 1550 nm, which are used in optical fiber communications. However, the course of the high-temperature instability of a quantum well structure, which is closely related to the diffusion of indium atoms, is still not clear due to the system’s complexity. The diffusion process of indium atoms was simulated by thermal treatment, and the changes in the optical and structural properties of an AlGaInAs quantum well are investigated in this paper. Compressive strained Al0.07Ga0.22In0.71As quantum wells were treated at 170 °C with different heat durations. A significant decrement of photoluminescence decay time was observed on the quantum well of a sample that was annealed after 4 h. The microscopic cathodoluminescent (CL) spectra of these quantum wells were measured by scanning electron microscope-cathodoluminescence (SEM-CL). The thermal treatment effect on quantum wells was characterized via CL emission peak wavelength and energy density distribution, which were obtained by spatially resolved cathodoluminescence. The defect area was clearly observed in the Al0.07Ga0.22In0.71As quantum wells layer after thermal treatment. CL emissions from the defect core have higher emission energy than those from the defect-free regions. The defect core distribution, which was associated with indium segregation gradient distribution, showed asymmetric character.

Carrier Dynamic Investigations of AlGaInAs Quantum Well Revealed by Temperature-Dependent Time-Resolved Photoluminescence

“…The X-ray diffraction pattern of the AlGaInAs QW structure is composed of a dominated InP diffraction peak localized at 63.345 °C (2 theta) and the QW’s multiorder satellite peaks at the side vicinity. More details about the structure property and growth method were presented in our previous work [ 14 ]. The AlGaInAs QW was measured by the temperature-dependent TRPL (HJY TRIX550; Original, USA).…”

“…Huang, et al [ 13 ]. PL decay of the thermal-treated AlGaInAs QW demonstrated that the effect of thermal process had a strong influence on the relaxation time of excitated carriers [ 14 ].…”

“…In our previous work, we investigated the mechanism of temperature-dependent PL peak energy of AlGaInAs QWs [ 14 ]. The dependencies and relationships between PL peak energy and FWHM vs. temperatures were discussed.…”