Overannealing effects in GaInNAs(Sb) alloys and their importance to laser applications

Abstract

The photoluminescence efficiency and linewidth are well-established metrics for characterizing potential laser active regions. We demonstrate the critical importance of a new parameter for predicting the performance of dilute-nitride lasers: the “optimal” postgrowth annealing temperature, defined as the annealing temperature giving the highest photoluminescence efficiency. We validate this assertion with two 1.55μm edge-emitting GaInNAsSb lasers containing active regions with different optimal annealing temperatures. Although both active regions showed comparable photoluminescence efficiency and linewidth under optimal annealing conditions, laser performance was significantly different. The room-temperature threshold current density for the active region with higher optimal annealing temperature was 630A∕cm2, compared with 2380A∕cm2 for the sample with lower optimal annealing temperature. We conclude that overannealing of the gain region during upper cladding growth is the responsible mechanism. The dependence of the optimal annealing temperature on composition and growth conditions is also discussed.

Development of GaInNAsSb alloys: Growth, band structure, optical properties and applications

“…This result is very striking, in that it runs contrary to all earlier reports of rapid degradation with increasing nitrogen content. We have found that adding more nitrogen is a better way of extending laser wavelength than adding indium [86], resulting in the lowest threshold 1.55 µm dilute nitride lasers to date.…”

“…In our case the lasing wavelength was successfully extended to 1.55 µm by increasing the nitrogen content [89]. It is worth noting that our initial attempts to extend the wavelength by increasing indium content were less successful, resulting in higher threshold current density, even though the optical quality of the PL sample was equivalent [86]. We suggest that the higher-indium GaInNAsSb active regions are damaged by the in-situ anneal during laser growth, and their weak thermal robustness is evidenced by the lower optimal anneal temperature of the PL samples.…”

“…In order to improve laser performance, room temperature PL measurements were performed for GaInNAsSb/GaNAs/GaAs QW structures grown at different temperatures [84], under different arsenic and antimony fluxes [85], and annealed under different conditions [86].…”

Influence of arsenic flux on the annealing properties of GaInNAs quantum wells for long wavelength laser applications around 1.6μm

“…Annealing is well-known to significantly improve the optical quality of dilute nitrides, but also severe degradation by overannealing has been reported [12]. The As flux has been shown to be one of the most important growth parameters during growth of GaInNAs QWs [3,4].…”

Nitrogen-electronegativity-induced bowing character in ternary zincblende Ga1−xInxN alloys

“…This has persuaded many investigators to deal with dilute nitride alloys (i.e., Ga 1−y In y N x As 1−x , with a nitrogen concentration x ≤ 6%) [8,9], in order to avoid lattice-distortion problems. The result is an almost exclusive concentration on telecommunication applications for * Tel.…”