Effect of unevenly-distributed V pits on the optical and electrical characteristics of green micro-light emitting diode

Da Hoon Lee, Daesung Kang, Tae Yeon Seong, Michael Kneissl, Hiroshi Amano

Research output: Contribution to journalArticle

Abstract

In this study, we investigated the effect of different-size V pits on the opto-electrical performance of different-size InGaN-based green (520 nm) light-emitting diodes (LEDs). The size of V pits varied from 57 to 250 nm. Two different-size LEDs (10 and 300 m) were fabricated with flip-chip structures. It was shown that at 4 A cm-2, the forward voltages of 300 m-size and 10 m-size LEDs were in the range of 2.32-2.82 V and 2.23-2.53 V, respectively. Compared with the LEDs with small V pits, the LEDs with large V pits produced higher output power at the high current region (>50 A cm-2), but lower output power at the low current region (<20 A cm-2). The 300 m-size LEDs displayed maximum external quantum efficiency (EQE) at 2 A cm-2, whereas the 10 m-size LEDs exhibited peak EQE at current densities 13 A cm-2. For all samples, the electroluminescence (EL) wavelengths were blue shifted with increasing current density. Unlike the 300 m-size LEDs, the 10 m-size LEDs exhibited a large deviation in the light output, EQE, and EL wavelength. The 10 m-size LEDs revealed larger S than the 300 m-size LEDs. The backscattered electron (BSE) and monochromatic cathodoluminescence (CL) results showed that for all samples, V pits were unevenly distributed across the whole wafer. Based on the CL and BSE results, the effect of different V pit sizes on the performance of green micro-LEDs at the low current region is described and discussed.

Original languageEnglish
Article number045106
JournalJournal of Physics D: Applied Physics
Volume53
Issue number4
DOIs
Publication statusPublished - 2020 Jan 1

Fingerprint

Light emitting diodes
light emitting diodes
Quantum efficiency
quantum efficiency
Cathodoluminescence
Electroluminescence
low currents
cathodoluminescence
electroluminescence
Current density
output
current density
Wavelength
Electrons
wavelengths
high current
electrons
chips
wafers
deviation

Keywords

  • Cathodoluminescence
  • Micro-light emitting diode
  • V pit size

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

Cite this

Effect of unevenly-distributed V pits on the optical and electrical characteristics of green micro-light emitting diode. / Lee, Da Hoon; Kang, Daesung; Seong, Tae Yeon; Kneissl, Michael; Amano, Hiroshi.

In: Journal of Physics D: Applied Physics, Vol. 53, No. 4, 045106, 01.01.2020.

Research output: Contribution to journalArticle

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