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- Khatab, A., et al.
(författare)
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Comparative Optical Studies of InGaAs/GaAs Quantum Wells Grown by MBE on (100) and (311)A GaAs Planes
- 2012
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Ingår i: Physica Status Solidi (C) Current Topics in Solid State Physics. - : Wiley. - 1610-1642 .- 1862-6351. ; 9:7, s. 1621-1623
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Tidskriftsartikel (refereegranskat)abstract
- The temperature dependence of the optical properties of InGaAs/GaAs double quantum wells (QWs) grown by molecular beam epitaxy (MBE) on (100) and (311)A GaAs substrates has been studied by photoluminescence (PL). It is found that for an excitation of 50 mW, the PL quenching for (100) and (311)A QWs occurs at 220 K and 300 K, respectively. This suggests that the high index plane (311)A has superior structural properties and less non-radiative defect centers than the conventional (100) plane. The better optical quality of the QWs grown on (311)A is also confirmed by the narrowing of the full width at half-maximum (FWHM) of the PL emission: 10 nm for (311)A and 20 nm for (100). From these findings it is expected that optical devices grown on (311)A GaAs planes should have better performances than those grown on conventional (100) orientation. We have also carried out a systematic study to investigate the effect of post-growth thermal annealing on the optical quality of the QWs. We observed a substantial improvement of the PL efficiency with annealing temperatures in the range 500-700 C for all samples. However, this PL enhancement is accompanied by a blueshift. These energy shifts can be explained by interdiffusion or intermixing of In and Ga atoms at the interfaces between the QWs and the barriers. A noticeable narrowing of the PL linewidth with higher annealing temperatures could be explained by a homogenisation of the quantum well interfaces.
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| 2. |
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| 3. |
- Largeau, L., et al.
(författare)
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Structural effects of the thermal treatment on a GaInNAs/GaAs superlattice
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 79:12, s. 1795-1797
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Tidskriftsartikel (refereegranskat)abstract
- We have studied structural changes that occur during annealing of GaInNAs/GaAs multiple quantum wells grown by metalorganic vapor-phase epitaxy (MOVPE). Different thermal treatments led to an improved room-temperature photoluminescence (PL) intensity, but also to room-temperature PL peak splitting. This splitting is related to the appearance of compositional clustering as displayed by transmission electron microscopy (TEM). In addition to this, interfacial layers on each side of the wells have also been observed by,TEM and their composition is discussed on the basis of high resolution x-ray diffraction studies. It is suggested that the interface layers are indium deficient, but enriched in nitrogen, degrading the optical quantum well performance and indicating a need for improved switching sequences in the MOVPE growth.
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