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Song, Hai‐Zhi; Akahane, Kouichi; Lan, Sheng; Xu, Huaizhe; Okada, Yoshitaka; Kawabe, Mitsuo

doi:10.1103/physrevb.64.085303

Cited by 34 publications

(23 citation statements)

References 31 publications

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“…MB transport controlled acoustic-phonon scattering was found in Ref. [71]. The existence of true miniband conduction via interface roughness scattering was highlighted by the authors of Ref.…”

Section: Temporal Profile Of Qdsl Plmentioning

confidence: 84%

“…Theoretical studies [61][62][63] and experimental observations of resonant tunneling [64,65] gave an impetus for a whole series of investigations of III-V-layer-based superlattices. Experimentally the miniband formation was found in type-I structures with III-V-based QDs by PL spectroscopy [66][67][68][69][70] and by photoconductivity [71]. The authors of Ref.…”

Section: Pl Excitation Power Dependencementioning

confidence: 99%

“…Hopping conduction was identified in the plane of QD arrays at low temperature in Ref. [71] for InGaAs and in Refs. [90,91] for Ge QDs.…”

Section: Temporal Profile Of Qdsl Plmentioning

confidence: 99%

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Miniband-related 1.4–1.8 μm luminescence of Ge/Si quantum dot superlattices

et al. 2006

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The luminescence properties of highly strained, Sb-doped Ge/Si multi-layer heterostructures with incorporated Ge quantum dots (QDs) are studied. Calculations of the electronic band structure and luminescence measurements prove the existence of an electron miniband within the columns of the QDs. Miniband formation results in a conversion of the indirect to a quasi-direct excitons takes place. The optical transitions between electron states within the miniband and hole states within QDs are responsible for an intense luminescence in the 1.4-1.8 lm range, which is maintained up to room temperature. At 300 K, a light emitting diode based on such Ge/Si QD superlattices demonstrates an external quantum efficiency of 0.04% at a wavelength of 1.55 lm.

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Section: Temporal Profile Of Qdsl Plmentioning

confidence: 84%

Section: Pl Excitation Power Dependencementioning

confidence: 99%

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Miniband-related 1.4–1.8 μm luminescence of Ge/Si quantum dot superlattices

et al. 2006

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“…The guiding element of the QD position is some unknown deposit, introducing defect-rich growth of QDs and then degradation of the QD coherence, which is fatal in QC. Selfassembly itself is sometimes capable of growing a rather ordered QD array [7], prospective due to an enhanced optical non-linearity, but it is impossible to prepare differently sized QDs at the same time. In this work, we use atomic force microscopy (AFM) oxidation to help controlling QDs.…”

mentioning

confidence: 99%

Precisely ordered quantum dot array formed using AFM lithography for all‐optical electron spin quantum computers

Ohshima

Song

Okada

et al. 2003

phys. stat. sol. (c)

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PACS 03.67. Lx, 68.65.Hb, 68.90.+g For application of quantum dots (QDs) in quantum computers, a precise control of self-assembled QDs was achieved in position and size. On a GaAs surface, atomic force microscope lithography is performed to fabricate nano-scaled oxide dots. When the oxide dots are suitably detached from the substrate, holes of the same size are formed. By overgrowing InGaAs on such a hole-patterned surface, one single quantum dot, whose size depends on the hole, is formed on the site of each hole. An ordered array of differently sized QDs can be fabricated as the qubits of all-optical quantum computer using electron spins of coupled QDs.1 Introduction Quantum computer (QC) research, which appeared in 1980's, has become more and more popular due to the discovery of quantum algorithms and the developments of experimental techniques in recent years [1]. Some physical implementations of quantum gates are proposed and demonstrated. Among them, solid state systems have an advantage of scalability, which is necessary for practical tasks. As a candidate of solid state QC, an electron system in semiconductor nanostructures is further advantageous of relatively controllable individual quantum states, which are particularly important in quantum gate operation. Accordingly, many QC schemes based on semiconductor quantum dots (QDs) have been proposed and studied [2,3]. To construct QC by using QDs, one of the most important challenges is to realize an arbitrarily ordered QD array, because self-assembled QDs grown in the Stranski−Krastanov (S−K) mode are usually randomly distributed. Although some techniques were developed, there are still many problems for them to be applied in QC. Defining holes by electron beam lithography is one of the widely used techniques, but the obtained dots are mostly still larger than 50 nm in diameter with an interdot distance above 100 nm [4,5] due to the proximity effect of the resist against electron beam. The large lateral separation prevents QDs from effective interdot coupling, which is fundamental in QC made of QDs. Scanning tunneling microscope (STM) lithography was also used to control self-assembled QDs [6]. The guiding element of the QD position is some unknown deposit, introducing defect-rich growth of QDs and then degradation of the QD coherence, which is fatal in QC. Selfassembly itself is sometimes capable of growing a rather ordered QD array [7], prospective due to an enhanced optical non-linearity, but it is impossible to prepare differently sized QDs at the same time. In this work, we use atomic force microscopy (AFM) oxidation to help controlling QDs. It is firstly advantageous of little defects and impurity. We can fabricate QD arrays with a size homogeneity of ±5%. The precision and reproducibility are satisfactory to the application in QC.

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“…In few cases, such an array can be self-organized by direct S-K growth. [4]. In recent years, self-assembled semiconductor QDs have been considered to be utilized in quantum information processing [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Site-controlled quantum dots fabricated using an atomic-force microscope assisted technique

et al. 2006

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An atomic-force microscope assisted technique is developed to control the position and size of self-assembled semiconductor quantum dots (QDs). Presently, the site precision is as good as ± 1.5 nm and the size fluctuation is within ± 5% with the minimum controllable lateral diameter of 20 nm. With the ability of producing tightly packed and differently sized QDs, sophisticated QD arrays can be controllably fabricated for the application in quantum computing. The optical quality of such site-controlled QDs is found comparable to some conventionally self-assembled semiconductor QDs. The single dot photoluminescence of sitecontrolled InAs/InP QDs is studied in detail, presenting the prospect to utilize them in quantum communication as precisely controlled single photon emitters working at telecommunication bands.

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In-plane photocurrent of self-assembledInxGa1−xAs

Cited by 34 publications

References 31 publications

Miniband-related 1.4–1.8 μm luminescence of Ge/Si quantum dot superlattices

Miniband-related 1.4–1.8 μm luminescence of Ge/Si quantum dot superlattices

Precisely ordered quantum dot array formed using AFM lithography for all‐optical electron spin quantum computers

Site-controlled quantum dots fabricated using an atomic-force microscope assisted technique

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