Volmer–Weber and Stranski–Krastanov InAs-(Al,Ga)As quantum dots emitting at 1.3 μm

Abstract

Mechanism for improvements of optical properties of 1.3-μ m InAs ∕ GaAs quantum dots by a combined InAlAs -InGaAs cap layer J. Appl. Phys. 98, 083516 (2005); 10.1063/1.2113408 Tuning InAs/GaAs quantum dot properties under Stranski-Krastanov growth mode for 1.3 μm applicationsSuppression of temperature sensitivity of interband emission energy in 1.3-μm-region by an InGaAs overgrowth on self-assembled InGaAs/GaAs quantum dots Quantum dots ͑QDs͒ formed on GaAs͑100͒ substrates by InAs deposition followed by ͑Al,Ga͒As or ͑In,Ga,Al͒As overgrowth demonstrate a photoluminescence ͑PL͒ peak that is redshifted ͑up to 1.3 m͒ compared to PL emission of GaAs-covered QDs. The result is attributed to redistribution of InAs molecules in the system in favor of the QDs, stimulated by Al atoms in the cap layer. The deposition of a 1 nm thick AlAs cover layer on top of the InAs-GaAs QDs results in replacement of InAs molecules of the wetting layer by AlAs molecules, leading to a significant increase in the heights of the InAs QDs, as follows from transmission electron microscopy. This effect is directly confirmed by transmission electron microscopy indicating a transition to a Volmer-Weber-like QD arrangement. We demonstrate an injection laser based on this kind of QDs.

InAs Quantum Dots in AlAs/GaAs Short Period Superlattices: Structure, Optical Characteristics and Laser Diodes

“…Generally, QD sizes increase with the growth temperature, and QDs on GaAs with 2ML AlAs overlayer exhibit the largest sizes. In the case of AlAs overlayer (as compared to GaAs), we have observed an increase of the average size and reduction of the surface density likely because of dissolving of small QDs and wetting layer by AlAs overlayer [14]. GaAs underlayer instead of AlAs also leads to increased size and reduced density of QDs.…”

“…This phenomenon of self-assembly is further complicated by intermixing of InAs QDs with the GaAs barrier [10], segregation of In atoms when InGaAs islands are overgrown by GaAs [11,12], complex diffusion properties of adatoms. Very recently, the top Al containing layers have been used to achieve a red shift of the InAs QDs photoluminescence band [13,14].…”

Effect of InxGa1−xAs strain release layers on the microstructural and interband transition properties of InAs/GaAs quantum dots

“…Among the many kinds of quantum structures, self-assembled quantum dots (QDs) in lattice-mismatched systems, such as In x Ga 1Àx As/GaAs [6] and In x Ga 1Àx As/InP QDs [7], can be achieved by using the Stranski-Krastanow (S-K) growth mode [8][9][10]. More recently, rapid advancements in semiconductor epitaxial growth technologies in molecular beam epitaxy (MBE) or metalorganic chemical vapor deposition methods have made possible the formation of defect-free InAs/GaAs QD systems [11,12], and the InAs/GaAs QDs have attracted much interest due to their potential applications in semiconductor lasers and fiber optical communication systems operating in the 1.3-mm region of the spectrum [13].…”

“…Even though QD-laser diodes (QD-LDs) are expected to achieve a high differential gain, a low threshold current density, and a high thermal stability [14,15], the performance of QD-LDs is still not good enough to overcome the inherent problems of devices operating at longer spectrum wavelength between 1.3 and 1.55 mm due to energy levels of the electronic states in the QDs [11,12]. The QD-LDs operating between 1.3 and 1.55 mm are of current interest because of their potential applications in optical communications and optical access networks; however, many problems still exist in controlling the size, homogeneity, and distribution of QDs, which significantly affect the emission wavelength and the linewidth.…”

High-quality InAs grown on GaAs substrate with an in situ micro-structured buffer

“…A high density of dislocations occurs in InAs epilayer, which leads to degradation of performance of the electronic devices. In order to obtain InAsbased or high In content InGaAs layers on GaAs substrates, several types of buffer layer technologies have been developed in the past [6][7][8][9][10][11][12]. However, most of these buffer layer growth techniques are time consuming and are not cost effective (requiring a long growth time).…”