Suppression of the photoluminescence quenching effect in self-assembled In As ∕ Ga As quantum dots The in-plane photoconductivity and photoluminescence are investigated in quantum dot-chain InGaAs/GaAs heterostructures. Different photoconductivity transients resulting from spectrally selecting photoexcitation of InGaAs QDs, GaAs spacers, or EL2 centers were observed. Persistent photoconductivity was observed at 80 K after excitation of electron-hole pairs due to interband transitions in both the InGaAs QDs and the GaAs matrix. Giant optically induced quenching of in-plane conductivity driven by recharging of EL2 centers is observed in the spectral range from 0.83 eV to 1.0 eV. Conductivity loss under photoexcitation is discussed in terms of carrier localiza-tion by analogy with carrier distribution in disordered media. V C 2014 AIP Publishing LLC.

No abstract

Electronic and optical properties of InAs/GaAs nanostructures grown by the droplet epitaxy method are studied. Carrier states were determined by k·p theory including effects of strain and In gradient concentration for a model geometry. Wavefunctions are highly localized in the dots. Coulomb and exchange interactions are studied and we found the system is in the strong confinement regime. Microphotoluminescence spectra and lifetimes were calculated and compared with measurements performed on a set of quantum rings in a single sample. Some features of spectra are in good agreement.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-016-1518-2) contains supplementary material, which is available to authorized users.

We studied the multilayering effects of InGaAs quantum dots (QDs) on GaAs(731), a surface lying inside of the stereographic triangle. The surfaces after stacking 16 InGaAs layers were characterized with highly non-uniformity of QD spatial distribution. The bunched step regions driven by strain accumulation are decorated by QDs, therefore GaAs(731) becomes a good candidate substrate for the growth of QD clusters. The unique optical properties of the QD clusters are revealed by photoluminescence measurements. By adjusting the coverage of InGaAs, a bamboo-like nanostructured surface was observed and the quantum dots aligned up in clusters to separate the "bamboo" into sections.

Utilizing the naturally curved surface contours provided by oval defects on a GaAs(100) surface, we demonstrate that alignment of quantum-dot chains formed during the growth of (In,Ga)As multilayers is unyielding to a modest deviation of surface orientation from (100) of about 0.7° along [01-1] and 8° along [011]. This finding suggests that the strain-driven kinetic anisotropy responsible for the formation of the quantum dot chains dominates over selective island formation at steps due to surface misorientation. The robustness of the quantum dot chain adds to its potential for its future application.

Structural, morphological, and defect properties of metamorphic In0.7Ga0.3As/GaAs0.35Sb0.65 p-type tunnel field effect transistor structure grown by molecular beam epitaxy Apparent critical thickness versus temperature for InAs quantum dot growth on GaAs (001) High-performance InAs/GaAs quantum-dot infrared photodetectors with a single-sided Al 0.3 Ga 0.7 As blocking layer Appl.Optical absorption spectra of intersubband transitions in In 0.3 Ga 0.7 As/ GaAs multiple quantum dots were investigated using the optical absorption as a function of the number of In 0.3 Ga 0.7 As monolayers deposited using the molecular-beam epitaxy Stranski-Krastanow technique. The peak position energy reached 13.7 m for a sample containing 50 monolayers of In 0.3 Ga 0.7 As. The lack of the observation of intersubband transitions in small quantum dots, where the number of the deposited monolayer is less than 15 monolayers, is an indication of the absence of quantum confinement. On the other hand, the presence of high dislocations density in larger quantum dots, where the deposited number of monolayers exceeds 50, could be the reason of why the intersubband transitions are degraded.

Photoluminescence of self-assembled InAs/GaAs quantum dots excited by ultraintensive femtosecond laser Photoluminescence from self-assembled long-wavelength InAs/GaAs quantum dots under pressure J. Appl. Phys. 95, 933 (2004); 10.1063/1.1635988Temperature dependence of intersublevel absorption in InAs/GaAs self-assembled quantum dots

We studied the multilayering effects of InGaAs quantum dots (QDs) on GaAs(731), a surface lying inside of the stereographic triangle. The surfaces after stacking 16 InGaAs layers were characterized with highly non-uniformity of QD spatial distribution. The bunched step regions driven by strain accumulation are decorated by QDs, therefore GaAs(731) becomes a good candidate substrate for the growth of QD clusters. The unique optical properties of the QD clusters are revealed by photoluminescence measurements. By adjusting the coverage of InGaAs, a bamboo-like nanostructured surface was observed and the quantum dots aligned up in clusters to separate the "bamboo" into sections. Most of the researches chose a surface index located between two low index planes out of the three, (100), (110), and (111). KeywordsIn other words, the popular choice was a surface index on the sides of the stereographic triangle defined by the three low index planes [3]. For example, GaAs(311), one of the most popular choice, locates between the (100) and (111)