Detailed Study of the Influence of InGaAs Matrix on the Strain Reduction in the InAs Dot-In-Well Structure

Abstract

InAs/InGaAs dot-in-well (DWELL) structures have been investigated with the systematically varied InGaAs thickness. Both the strained buffer layer (SBL) below the dot layer and the strain-reducing layer (SRL) above the dot layer were found to be responsible for the redshift in photoluminescence (PL) emission of the InAs/InGaAs DWELL structure. A linear followed by a saturation behavior of the emission redshift was observed as a function of the SBL and SRL thickness, respectively. The PL intensity is greatly enhanced by applying both of the SRL and SBL. Finite element analysis simulation and transmission electron microscopy (TEM) measurement were carried out to analyze the strain distribution in the InAs QD and the InGaAs SBL. The results clearly indicate the strain reduction in the QD induced by the SBL, which are likely the main cause for the emission redshift.

Interband Photoconductivity of Metamorphic InAs/InGaAs Quantum Dots in the 1.3–1.55-μm Window

“…Their most attractive feature is that, by growing the QDs on an InGaAs metamorphic buffer (MB), one can achieve a significant reduction of the transition energy between the QD levels [ 8 ] with respect to conventional In(Ga)As/GaAs QD structures. This occurs due to the decrease of InAs QD bandgap as a result of the lattice mismatch reduction between InAs QDs and InGaAs buffer and, hence, the strain in QDs [ 9 – 11 ]. So, the application of a MB as a confining material allows to shift the emission wavelength value deeper into the infrared (IR) range, in particular, into the telecommunication windows at 1.3 and 1.55 μm, while maintaining a high efficiency [ 4 , 12 , 13 ].…”

Bipolar Effects in Photovoltage of Metamorphic InAs/InGaAs/GaAs Quantum Dot Heterostructures: Characterization and Design Solutions for Light-Sensitive Devices

“…For example, the photosensitivity range can be extended via the excitation through intermediate bandgap [ 17 , 18 ] or multiple exciton generation [ 19 , 20 ], so that the power conversion efficiencies of QD-based solar cells can exceed in theory the limits of single-bandgap solar cells [ 21 ]. The methods like strain-balancing [ 22 ] and misfit management technique [ 23 ] as well as the thermal annealing [ 24 ] are used to reduce strains in these structures, operating the working range [ 25 ] as well as increasing the photoresponse due to the suppression of strain-related defects [ 26 ] that can act as recombination centers.…”

“…As a result, InAs/InGaAs QD structures have attracted much interest in last decade [ 27 – 29 ]. By growing the QDs on the InGaAs MB, one can observe essential differences in the formation process and QD optical properties compared with conventional ones in GaAs matrix [ 25 , 30 – 33 ]. For example, the InGaAs confining layer reduces the lattice mismatch between QDs and buffer and, hence, strains in QDs.…”

“…As well, there have been hopeful attempts to apply the photoelectric properties of the metamorphic InAs QD structures on the design of such light-sensitive devices as metamorphic infrared photodetectors [ 11 – 13 ] and solar cells [ 37 – 39 ]. Some studies were carried out to develop structure design [ 25 , 31 – 33 ] and other ones to improve photoelectric properties [ 39 , 40 ]. Investigations are going on to reduce the strains in the heterostructures [ 34 , 41 ], as this leads to a substantial improvement in the photocurrent density and spectral response of solar cells [ 39 , 40 ] as well as in the photoemission efficiency of such structures [ 29 , 32 , 42 ].…”

Гетероструктуры AlInPSbAs/InAs для термофотоэлектрических преобразователей

“…Таковыми являются пятикомпонентные твердые растворы соединений A 3 B 5 , совпадающие по параметрам решетки и коэффициенту термического расширения (КТР) с подложками [5]. Перспективными материалами для термофотоэлектрических преобразователей служат многокомпонентные твердые растворы на основе InAs [6][7][8].…”