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. 2014 Jun 5:4:5166.
doi: 10.1038/srep05166.

High density GaN/AlN quantum dots for deep UV LED with high quantum efficiency and temperature stability

Weihuang Yang  1 , Jinchai Li  1 , Yong Zhang  2 , Po-Kai Huang  3 , Tien-Chang Lu  3 , Hao-Chung Kuo  3 , Shuping Li  1 , Xu Yang  1 , Hangyang Chen  1 , Dayi Liu  1 , Junyong Kang  1
Affiliations

High density GaN/AlN quantum dots for deep UV LED with high quantum efficiency and temperature stability

Weihuang Yang et al. Sci Rep. .

Abstract

High internal efficiency and high temperature stability ultraviolet (UV) light-emitting diodes (LEDs) at 308 nm were achieved using high density (2.5 × 10(9) cm(-2)) GaN/AlN quantum dots (QDs) grown by MOVPE. Photoluminescence shows the characteristic behaviors of QDs: nearly constant linewidth and emission energy, and linear dependence of the intensity with varying excitation power. More significantly, the radiative recombination was found to dominant from 15 to 300 K, with a high internal quantum efficiency of 62% even at room temperature.

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Figures

Figure 1
Figure 1. (a) SEM, (b) size distribution, (c) cross-sectional TEM image and (d) Raman spectrum of the self-assembled GaN/AlN QDs grown on n- Al0.7Ga0.3N, respectively.
Figure 2
Figure 2. Power–dependent PL taken at room temperature.
(a) Power-dependent PL spectra of the GaN/AlN QDs at 300 K. Inset shows the CL spectrum and monochromatic CL mapping at wavelength of 309 nm at 300 K. (b) Spectral width, (c) integrated intensity and (d) peak wavelength of the PL spectrum as a function of excitation power, respectively.
Figure 3
Figure 3. Temperature–dependent TRPL taken in temperatures ranging from 15 K to 300 K.
(a) TRPL spectra for GaN/AlN QDs as a function of temperature (15–300 K). (b) Temperature-dependent decay time (closed circles), radiative (open circles) and nonradiative lifetimes (open squares). (c) Temperature-dependent PL efficiency (closed squares).
Figure 4
Figure 4. Electrical characteristics of GaN/AlN QDs UV LED.
(a) EL spectra from the GaN/AlN QDs UV LED with varying DC current at RT. Insets depict the current-voltage characteristics of the fabricated GaN/AlN-QD UV-LED chip and visible blue emission from blue phosphors excited by the UV emission. (b) The temperature distributions of the UV-LED chip under different injection currents. (c) Wavelength shift of the UV-LED chip in the 1.0–100 mA range with respect to 1.0 mA.
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References

    1. Fujikawa S., Takano T., Kondo Y. & Hirayama H. Realization of 340-nm-band high-output-power (>7 mW) InAlGaN quantum well ultraviolet light-emitting diode with p-type InAlGaN. Jpn. J. Appl. Phys. 47, 2941 (2008).
    1. Hirayama H., Noguchi N., Yatabe T. & Kamata N. 227 nm AlGaN light-emitting diode with 0.15 mW output power realized using a thin quantum well and AlN buffer with reduced threading dislocation density. Appl. Phys. Express 1, 051101 (2008).
    1. Khan A., Balakrishnan K. & Katona T. Ultraviolet light-emitting diodes based on group three nitrides. T. Nature Photonics 2, 77 (2008).
    1. Chitnis A. et al. Improved performance of 325-nm emission AlGaN ultraviolet light-emitting diodes. Appl. Phys. Lett. 82, 2565 (2003).
    1. Adivarahan V. et al. Robust 290 nm emission light emitting diodes over pulsed laterally overgrown AlN. Jpn. J. Appl. Phys. 46, L877 (2007).

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