High-temperature performance in ∼4 μm type-II quantum well lasers with increased strain
2002; American Institute of Physics; Volume: 92; Issue: 10 Linguagem: Inglês
10.1063/1.1513199
ISSN1520-8850
AutoresAndrew P. Ongstad, R. Kaspi, J. R. Chavez, Gregory C. Dente, Michael L. Tilton, Donald M. Gianardi,
Tópico(s)Semiconductor Quantum Structures and Devices
ResumoIn this article, we report on a systematic study of mid-IR, W-Integrated Absorber (W-IA), lasers that employ strained InAs/InxGa1−xSb/InAs active layers, in which the indium content of the hole bearing InxGa1−xSb has been varied from xIn=0 to xIn=0.45. The output characteristics of the lasers improve as the In percentage is increased; the threshold temperature sensitivity (T0) values are observed to increase from ≈35 to ≈50 K. Further, the differential quantum efficiencies as a function of temperature are significantly improved in the devices with xIn⩾0.25. For samples with nominally eight monolayers (8 ML) InAs/7 ML InxGa1−xSb/8 ML InAs, the lasing wavelength at 84 K is observed to shift from 3.33 μm for xIn=0 out to a maximum of 4.62 μm for xIn=0.35. This large shift is well predicted by an empirical psuedopotential model; the model also predicts that the position of the hole wave function is sensitively dependent on strain level and that for xIn<0.25, the holes are no longer confined in the W active region, but rather in the thick IA layers where they experience a bulklike density of states. This suggests that the improved thermal performance with increasing strain is due to the onset of hole quantum confinement in the W region, and improved or deeper hole confinement in that epitaxial layer.
Referência(s)