Influence of barrier layers on indium segregation in pseudomorphic InGaAs/(Al)GaAs quantum wells grown by MOCVD

Abstract

The indium atom distribution in InGaAs/(Al)GaAs quantum wells (QWs) grown by metal-organic chemical vapour deposition was systematically studied. High-resolution grazing-sputter-angle Auger electron spectroscopy was used as a method of indium depth profile investigation. A broadening and shift to the surface of the indium concentration profile in a single QW and an increase of indium content in the upper QW for closely spaced QWs were found. These results were confirmed by photoluminescence measurements. It was observed that the use of AlGaAs barriers between QWs and growth interruptions at QW interfaces during the growth process reduce indium surface segregation.

Improved optical properties of InAs quantum dots for intermediate band solar cells by suppression of misfit strain relaxation

“…The upper layer results from trapping of indium that is segregated during growth of the GaAs capping layer, 26 and is blocked by the AlGaAs barrier. 27 For sample B (Fig. 2(c)), the dots have a uniform height resulting from the 5-nm-thick capping layer, with a flat top surface due to the truncation of its top portion by the lateral diffusion induced by …”

μ‐EXAFS, μ‐XRF, and μ‐PL Characterization of a Multi‐Quantum‐Well Electroabsorption Modulated Laser Realized via Selective Area Growth

“…In the field of semiconductor bandgap engineering, the frontier of research is represented by 1D‐ and 0D‐confined systems, usually named quantum wires1–6 and quantum dots, respectively 7, 8. Nevertheless, for several practical reasons, the economical market of III–V quantum lasers is still dominated by 2D‐confined quantum well and multi quantum well (MQW) heterostructures that are currently widely used in optical communication systems 9–17. They are deposited on suitable substrates using appropriate growth techniques, like molecular beam epitaxy (MBE)16 or metal–organic vapor‐phase epitaxy (MOVPE) 12, 15, 18.…”

“…Nevertheless, for several practical reasons, the economical market of III–V quantum lasers is still dominated by 2D‐confined quantum well and multi quantum well (MQW) heterostructures that are currently widely used in optical communication systems 9–17. They are deposited on suitable substrates using appropriate growth techniques, like molecular beam epitaxy (MBE)16 or metal–organic vapor‐phase epitaxy (MOVPE) 12, 15, 18. The MOVPE growth process starts from group III (metal organics) and group V (hydrides) precursors that are thermally decomposed and subsequently deposited uniformly on the substrate, rebuilding the crystal lattice layer by layer with the desired composition.…”

Terahertz quantum cascade laser considering compositional interdiffusion effect

“…abrupt interfaces without any interdiffusion) with an axialdependent broadened potential profile in the one-dimensional Schrödinger equation solver, indicating that interdiffusion can distort subband wave functions and shift levels energy. 14,15) Several experimental techniques, such as transmission electron microscopy (TEM), 16) atom probe tomography, 17) and Auger electron spectroscopy (AES) 18) have been employed to determine the composition profile across interfaces, and the error or sigmoidal functions are frequently utilized to fit those profiles. For GaAs/(Al,Ga)As quantum wells, an Al interdiffusion width is determined by 3-5 monolayers (1 ML = 0.2825 nm).…”