Ultraviolet light-emitting diodes with self-assembled InGaN quantum dots

Park, Il‐Kyu; Kwon, Min‐Ki; Seo, Seong-Bum; Kim, Ja‐Yeon; Lim, Jae-Hong; Park, Seong-Ju

doi:10.1063/1.2712804

Cited by 35 publications

(30 citation statements)

References 21 publications

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“…Thus, there has been a growing effort over the past few years concerning intentionally grown InGaN QD based LEDs [59,60]. The investigated LED structure shows an onset voltage of 3.15 V at room temperature, and the QD ensemble EL band covers the spectral region from 2.2 to 2.6 eV.…”

Section: Electroluminescence Of Single Qdsmentioning

confidence: 99%

Optical properties of single InGaN quantum dots and their devices

Sebald

Kalden

Lohmeyer

et al. 2011

Physica Status Solidi (b)

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Nitride-based quantum dots have many attractive optical properties for the realization of quantum dot (QD) based devices which will be presented in this contribution. We will analyze the basic characteristics of single InGaN QDs and their electroluminescence (EL) as well as the optical properties of QD stacks and their gain spectra. The single QDs are characterized by the high temperature stability of their emission up to 150 K in PL and EL and even up to room temperature for stacked QD samples. Furthermore, the polarization of individual QD emission lines was analyzed giving an insight into their geometrical shape. Time-resolved microphotoluminescence (m-PL) measurements on the excitonic and biexcitonic transition of a single QD as well as on the influence of piezoelectric fields on them and on their binding energy were performed. Further, we present an analysis of electrically driven luminescence from single InGaN QDs embedded into a light emitting diode structure showing single sharp emission lines in the green spectral region with a high temperature stability up to 150 K. Furthermore, for the possible integration within optical devices in the future the threshold power density as well as the modal gain were investigated for samples with stacked InGaN QD layers. They show a modal gain per QD being comparable to that of II-VI and III-As compounds. These results give a good insight into the basic optical properties of InGaN QD based devices and showing their high potential for electrically driven single photon emitters as well as for bright, low-threshold InGaN QD based light emitting devices in the near future.

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Section: Electroluminescence Of Single Qdsmentioning

confidence: 99%

Optical properties of single InGaN quantum dots and their devices

Sebald

Kalden

Lohmeyer

et al. 2011

Physica Status Solidi (b)

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“…To improve the emission efficiency of an UV LED, an alternate active layer with QDs has been used due to its enhanced exciton binding energy and carrier localization effect [48]. Recently, UV LEDs with self-assembled InGaN QDs grown in a strain-induced S-K mode have been reported for the first time by I. K. Park et al [49]. And in the same year, they demonstrated green LEDs with phase-separated In-rich InGaN QDs embedded in the InGaN active layer [50].…”

Section: High-brightness Uv Leds Have Great Advantages Inmentioning

confidence: 99%

III-Nitride-Based Quantum Dots and Their Optoelectronic Applications

Weng

Ling

et al. 2011

Nano-Micro Lett.

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During the last two decades, III-nitride-based quantum dots (QDs) have attracted great attentions for optoelectronic applications due to their unique electronic properties. In this paper, we first present an overview on the techniques of fabrication for III-nitride-based QDs. Then various optoelectronic devices such as QD lasers, QD light-emitting diodes (LEDs), QD infrared photodetectors (QDIPs) and QD intermediate band (QDIB) solar cells (SCs) are discussed. Finally, we focus on the future research directions and how the challenges can be overcome.

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“…Since these QDs are formed via strain relaxation during the growth of highly lattice-mismatched heteroepitaxy systems, controllability of the shape and size are limited by the total energy of the strained epilayer/substrate system. As a result, the height of InGaN QDs grown via a S-K growth mode is difficult to control without changing the lateral size [5], and is usually much smaller than the diameter, resulting in a small aspect ratio well below 1 [3][4][5][6]. Numerical calculations showed that the electron wave function in the QDs can penetrate significantly into the barrier for QDs with a small aspect ratio, resulting in reduced confinement of the electron wave function in the vertical direction and in an overlap integral between the electron and hole wave functions [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, InGaN-based self-assembled quantum dots (QDs) grown via the strain-induced Stranski-Krastanov (S-K) growth mode have attracted much attention for possible use in advanced light-emitting devices and quantum information applications [1][2][3][4]. Since these QDs are formed via strain relaxation during the growth of highly lattice-mismatched heteroepitaxy systems, controllability of the shape and size are limited by the total energy of the strained epilayer/substrate system.…”

Section: Introductionmentioning

confidence: 99%