Does In form In-rich clusters in InGaN quantum wells?

Humphreys, C. J.

doi:10.1080/14786430701342172

Cited by 88 publications

(71 citation statements)

References 34 publications

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“…Studies [36] have shown that InGaN is a random alloy in which indium atoms distribute randomly but uniformly, and that they do not form the so-called indium-rich islands of the nanometer-length scale especially when the indium fraction is as low as x = 15 % as in our case. In a disk-shaped In 0.…”

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confidence: 89%

“…Such sharp diameter cut-off provides strong evidence that the formation of our QDs is not due to the random inclusion of so-called localization centers (LCs). Such LCs, expected to be a few nanometers large in the lateral dimension, [36] could form due to QW thickness fluctuations or at indium-rich islands. The sharp intensity cut-off at ∼ 15 nm clearly suggests that the emission intensity is correlated with the size of the entire InGaN disk rather than small few-nanometer-scale LCs within the InGaN disk.…”

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confidence: 99%

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Single photon emission from site-controlled InGaN/GaN quantum dots

Zhang

Teng

Hill

et al. 2013

Applied Physics Letters

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Single photon emission was observed from site-controlled InGaN/GaN quantum dots. The singlephoton nature of the emission was verified by the second-order correlation function up to 90 K, the highest temperature to date for site-controlled quantum dots. Micro-photoluminescence study on individual quantum dots showed linearly polarized single exciton emission with a lifetime of a few nanoseconds. The dimensions of these quantum dots were well controlled to the precision of state-of-the-art fabrication technologies, as reflected in the uniformity of their optical properties. The yield of optically active quantum dots was greater than 90%, among which 13%-25% exhibited single photon emission at 10 K.Semiconductor quantum dots (QDs) have diverse quantum photonic applications [1,2] [2] However, most work to date has been based on self-assembled QDs in III-As and III-P materials, which face severe limitations in operating temperature and scalability. III-As and III-P QDs typically operate at cryogenic temperatures due to the relatively small exciton binding energies and QD-barrier band offsets. Furthermore, self-assembled QDs are formed at random locations and suffer from large inhomogeneity in size and spectral distribution, which prevents controlled coupling of multiple QDs or coupling of QDs with cavities. In this letter, we report single photon emission from sitecontrolled single InGaN/GaN QDs that are scalable for manufacturing and can be readily integrated with cavities.To achieve cryo-free operation, III-N QDs with large QD-barrier band offsets and exciton binding energies have emerged as one of the most promising solutions. Single photon emission has been reported up to 200 K, although only in a self-assembled GaN/AlN QD[10] and an InGaN QD in a self-organized AlGaN nanowire. [11] To control the position of a III-N QD, various approaches have been explored. [12][13][14][15][16][17][18] To date, QD-like emission has only been reported from dots formed at the apex of a sitecontrolled GaN pyramid [12,17] and dots at the top of a site-controlled AlGaN nanowire.[18] But no single photon emission has been reported from these systems yet.In this work, we fabricated site-controlled InGaN/GaN QDs by dry etching of a planar single quantum well * dengh@umich.edu † peicheng@umich.edu (QW). This structure has been applied to III-As systems but with very limited success, due to the detrimental surface effects introduced by the etched sidewall. [19] In contrast, the surface recombination velocity of III-N is 2-3 orders of magnitude slower than that of IIIAs. [20,21] Bright luminescence has been observed from ensembles of III-N nano-pillars etched from multiple QW structures, [13][14][15] and from a single quantum disk at the room temperature.[22] Yet no clear evidence of single photon emission from these structures have been reported so far. Here we not only show single photon emission from our lithographically defined, scalable single InGaN/GaN QDs but also show that this quantum phenomenon survives at temperatures up to 90...

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confidence: 89%

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Single photon emission from site-controlled InGaN/GaN quantum dots

Zhang

Teng

Hill

et al. 2013

Applied Physics Letters

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“…The reason that InGaN LEDs are much more tolerant of TDs than other conventional III-V materials is probably due to carrier localisation effects [20][21][22][23][24][25][26]. The first contributing factor is the monolayer height interface steps on the InGaN quantum wells.…”

Section: à2mentioning

confidence: 99%

Solid-State Lighting Based on Light Emitting Diode Technology

Zhu

Humphreys

2016

Optics in Our Time

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“…Second, electronic structure calculations have predicted strong hole localization even in the absence of compositional inhomogeneities [6], with preferential localization along randomly formed [1,1,0] In-NIn-N-In chains [39]. Finally, InGaN QW width fluctuations (even as small as one monolayer) have been proposed as an effective mechanism to provide localization energies above kT at room temperature [31].…”

Section: Extended Defectsmentioning

confidence: 99%

Research challenges to ultra‐efficient inorganic solid‐state lighting

Phillips¹,

Coltrin

Crawford

et al. 2007

Laser & Photonics Reviews

375

268

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Solid-state lighting is a rapidly evolving, emerging technology whose efficiency of conversion of electricity to visible white light is likely to approach 50% within the next several years. This efficiency is significantly higher than that of traditional lighting technologies, giving solid-state lighting the potential to enable significant reduction in the rate of world energy consumption. Further, there is no fundamental physical reason why efficiencies well beyond 50% could not be achieved, which could enable even more significant reduction in world energy usage. In this article, we discuss in some detail: (a) the several approaches to inorganic solid-state lighting that could conceivably achieve "ultra-high," 70% or greater, efficiency, and (b) the significant research questions and challenges that would need to be addressed if one or more of these approaches were to be realized.

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Does In form In-rich clusters in InGaN quantum wells?

Cited by 88 publications

References 34 publications

Single photon emission from site-controlled InGaN/GaN quantum dots

Single photon emission from site-controlled InGaN/GaN quantum dots

Solid-State Lighting Based on Light Emitting Diode Technology

Research challenges to ultra‐efficient inorganic solid‐state lighting

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