Influence of GaNAs strain-compensation layers on the optical properties of GaIn(N)As∕GaAs quantum wells upon annealing

Abstract

Articles you may be interested inStructural characterization of metal organic vapor phase epitaxy grown GaInNAs quantum well with InGaAs and GaNAs barriers GaIn͑N͒As/ GaAs and GaIn͑N͒As/ GaNAs/ GaAs quantum well ͑QW͒ samples, with and without GaNAs strain-compensating layers ͑SCLs͒, were grown on GaAs ͑001͒ substrates by molecular beam epitaxy. Photoluminescence ͑PL͒ was used to study the effects of the GaNAs SCL on the properties of the Ga͑In͒NAs QWs upon annealing. We observed that the insertion of GaNAs SCL produced a distinct increase in the PL blueshift as a function of annealing time. X-ray diffraction from the strain-compensated GaIn͑N͒As QWs before and after annealing showed no N atom diffusion, but exhibited Ga-In atom interdiffusion across the QW interfaces. We compared the effects of the GaNAs SCL on the PL blueshift with those of the SiO 2 encapsulant upon annealing. The increased PL blueshift caused by the GaNAs SCL for t ann ഛ 40 s is attributed to the further Ga m In 4−m -N ͑0 ഛ m ഛ 4͒ changes due to greater local strain caused by GaNAs ͑SCL͒ quantum barriers as compared with GaAs barriers. For t ann Ͼ 40 s, the nonsaturable blueshift caused by GaNAs SCL is attributed to defect-assisted ͑especially, Ga vacancies͒ Ga/ In interdiffusion, since the density of Ga vacancy defects in the GaNAs SCLs is quite high.

Anneal-induced structural changes of GaIn(N)As/Ga(N)As multiple quantum wells grown by molecular beam epitaxy

“…[11] on assumption that the QWs retain their square shape and alloy homogeneity, while dissolving the barriers during annealing. No nitrogen diffusion was considered in the simulations [12,13]. It should be noted that the incorporation of N is found to modify the In concentration profile for the as-grown samples due to In-surface segregation [14].…”

Annealing effects on InGaAsN∕GaAs quantum wells analyzed using thermally detected optical absorption and ten band k−p calculations

“…17,18 During the growth at low temperature, defects appear which number is possibly reduced by thermal annealing via a diffusion mechanism. For sample B ͑nominal N concentration equal to 0.7%͒, the transition blueshifts are 68, 57, and 48 meV for e 1 hh 1 , e 1 lh 1 , and e 2 hh 2 , respectively, and 79, 68, and 75 meV for sample C ͑nominal N concentration: 1.8%͒.…”

“…3͒ in the case of the annealed samples. 18 The incorporation of N in the GaAs layer induces Ga vacancies favoring the In-Ga interdiffusion. This conclusion is in agreement with published results.…”

“…The values of the diffusion lengths extracted from the experimental data are 16 and 21 Å similar to the 14.5 Å obtained for the InGaAs/ GaAs system. 18 due to the residual amount of nitrogen in the GaAs barriers and the FIG. Even if Mussler et al 17 demonstrated the inhibition of the In/ Ga interdiffusion process due to N incorporation in InGaAsN/ GaAs QWs, in contrast, the enhancement of the In-Ga interdiffusion is clearly evidenced when GaNAs strain-compensation layers are grown between the InGaAsN well and the GaAs barriers.…”

An analysis of Hall mobility in as-grown and annealed n- and p-type modulation-doped GaInNAs/GaAs quantum wells

“…Even though the addition of N strongly affects the electron effective mass, the presence of N has a negligible effect on the valance band and hole effective mass according to the k·p model [ 8 - 13 ]. An effective method is post or in situ thermal annealing which improves optical and crystal quality [ 14 - 16 ].…”