Electrical, spectral and optical performance of yellow-green and amber micro-pixelated InGaN light-emitting diodes

Zheng Gong, N.Y. Liu, Y.B. Tao, David Massoubre, E.Y Xie, X.D. Hu, Z.Z. Chen, G.Y. Zhang, Y.B. Pan, M.S. Hao, Ian Watson, Erdan Gu, Martin Dawson

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Micro-pixelated InGaN LED arrays operating at 560 and 600 nm, respectively, are demonstrated for what the authors believe to be the first time. Such devices offer applications in areas including bioinstrumentation, visible light communications and optoelectronic tweezers. The devices reported are based on new epitaxial structures, retaining conventional (0 0 0 1) orientation, but incorporating electron reservoir layers which enhance the efficiency of radiative combination in the active regions. A measured output optical power density up to 8 W cm−2 (4.4 W cm−2) has been achieved from a representative pixel of the yellow–green (amber) LED array, substantially higher than that from conventional broad-area reference LEDs fabricated from the same wafer material. Furthermore, these micro-LEDs can sustain a high current density, up to 4.5 kA cm−2, before thermal rollover. A significant blueshift of the emission wavelength with increasing injection current is observed, however. This blueshift saturates at 45 nm (50 nm) for the yellow–green (amber) LED array, and numerical simulations have been used to gain insight into the responsible mechanisms in this microstructured format of device. In the relatively low-current-density regime (<3.5 kA cm−2) the blueshift is attributable to both the screening of the piezoelectric field by the injected carriers and the band-filling effect, whereas in the high-current regime, it is mainly due to band-filling. Further development of the epitaxial wafer material is expected to improve the current-dependent spectral stability.
Original languageEnglish
Article number015003
JournalSemiconductor Science and Technology
Volume27
Issue number1
DOIs
Publication statusPublished - Jan 2012

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Amber
Light emitting diodes
light emitting diodes
high current
Current density
wafers
current density
low currents
retaining
bioinstrumentation
Biosensors
Optoelectronic devices
format
optical communication
radiant flux density
Screening
screening
Pixels
pixels
injection

Keywords

  • photonics
  • optics
  • InGaN light-emitting diodes

Cite this

Gong, Zheng ; Liu, N.Y. ; Tao, Y.B. ; Massoubre, David ; Xie, E.Y ; Hu, X.D. ; Chen, Z.Z. ; Zhang, G.Y. ; Pan, Y.B. ; Hao, M.S. ; Watson, Ian ; Gu, Erdan ; Dawson, Martin. / Electrical, spectral and optical performance of yellow-green and amber micro-pixelated InGaN light-emitting diodes. In: Semiconductor Science and Technology. 2012 ; Vol. 27, No. 1.
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abstract = "Micro-pixelated InGaN LED arrays operating at 560 and 600 nm, respectively, are demonstrated for what the authors believe to be the first time. Such devices offer applications in areas including bioinstrumentation, visible light communications and optoelectronic tweezers. The devices reported are based on new epitaxial structures, retaining conventional (0 0 0 1) orientation, but incorporating electron reservoir layers which enhance the efficiency of radiative combination in the active regions. A measured output optical power density up to 8 W cm−2 (4.4 W cm−2) has been achieved from a representative pixel of the yellow–green (amber) LED array, substantially higher than that from conventional broad-area reference LEDs fabricated from the same wafer material. Furthermore, these micro-LEDs can sustain a high current density, up to 4.5 kA cm−2, before thermal rollover. A significant blueshift of the emission wavelength with increasing injection current is observed, however. This blueshift saturates at 45 nm (50 nm) for the yellow–green (amber) LED array, and numerical simulations have been used to gain insight into the responsible mechanisms in this microstructured format of device. In the relatively low-current-density regime (<3.5 kA cm−2) the blueshift is attributable to both the screening of the piezoelectric field by the injected carriers and the band-filling effect, whereas in the high-current regime, it is mainly due to band-filling. Further development of the epitaxial wafer material is expected to improve the current-dependent spectral stability.",
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Electrical, spectral and optical performance of yellow-green and amber micro-pixelated InGaN light-emitting diodes. / Gong, Zheng; Liu, N.Y.; Tao, Y.B.; Massoubre, David; Xie, E.Y; Hu, X.D. ; Chen, Z.Z.; Zhang, G.Y.; Pan, Y.B.; Hao, M.S.; Watson, Ian; Gu, Erdan; Dawson, Martin.

In: Semiconductor Science and Technology, Vol. 27, No. 1, 015003, 01.2012.

Research output: Contribution to journalArticle

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T1 - Electrical, spectral and optical performance of yellow-green and amber micro-pixelated InGaN light-emitting diodes

AU - Gong, Zheng

AU - Liu, N.Y.

AU - Tao, Y.B.

AU - Massoubre, David

AU - Xie, E.Y

AU - Hu, X.D.

AU - Chen, Z.Z.

AU - Zhang, G.Y.

AU - Pan, Y.B.

AU - Hao, M.S.

AU - Watson, Ian

AU - Gu, Erdan

AU - Dawson, Martin

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