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Fabrication and characterization of GaN-based light-emitting diodes without pre-activation of p-type GaN.

Hu XL, Wang H, Zhang XC - Nanoscale Res Lett (2015)

Bottom Line: During the fabrication process, a 100-nm-thick indium tin oxide film was served as the p-type contact layer and annealed at 500°C in N2 ambient for 20 min to increase its transparency as well as to activate the p-type GaN.We discussed the mechanism of activation of p-type GaN at 500°C in N2 ambient.Furthermore, x-ray photoemission spectroscopy examinations were carried out to study the improved electrical performances of the LEDs without pre-activation of p-type GaN.

View Article: PubMed Central - PubMed

Affiliation: Engineering Research Center for Optoelectronics of Guangdong Province, School of Physics and Optoelectronics, South China University of Technology, Guangzhou, Guangdong 510640 China.

ABSTRACT
We fabricated GaN-based light-emitting diodes (LEDs) without pre-activation of p-type GaN. During the fabrication process, a 100-nm-thick indium tin oxide film was served as the p-type contact layer and annealed at 500°C in N2 ambient for 20 min to increase its transparency as well as to activate the p-type GaN. The electrical measurements showed that the LEDs were featured by a lower forward voltage and higher wall-plug efficiency in comparison with LEDs using pre-activation of p-type GaN. We discussed the mechanism of activation of p-type GaN at 500°C in N2 ambient. Furthermore, x-ray photoemission spectroscopy examinations were carried out to study the improved electrical performances of the LEDs without pre-activation of p-type GaN.

No MeSH data available.


Integrated PL intensity of two LED epitaxial wafers. The inset shows the PL spectra of two wafers.
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Fig1: Integrated PL intensity of two LED epitaxial wafers. The inset shows the PL spectra of two wafers.

Mentions: Figure 1 shows the integrated PL intensity of LED epitaxial wafers pre-annealed at 800°C in N2 ambient for 20 min and pre-annealed at 500°C in O2 ambient for 10 min. The inset shows the PL spectra of the two wafers. The integrated PL intensity of the wafers is the average value of 100 points measured from the entire 2-in. epitaxial layers. Assuming the integrated PL intensity of as-grown wafer is 100, the intensities of the wafers pre-annealed at 800°C and pre-annealed at 500°C are decreased to 83.4% and 99.2%, respectively. The obvious decrease in the integrated PL intensity of the wafer pre-annealed at 800°C is due to the increased non-radiative recombination that caused by the defects generated during the high-temperature thermal annealing process [11,19,20].Figure 1


Fabrication and characterization of GaN-based light-emitting diodes without pre-activation of p-type GaN.

Hu XL, Wang H, Zhang XC - Nanoscale Res Lett (2015)

Integrated PL intensity of two LED epitaxial wafers. The inset shows the PL spectra of two wafers.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385135&req=5

Fig1: Integrated PL intensity of two LED epitaxial wafers. The inset shows the PL spectra of two wafers.
Mentions: Figure 1 shows the integrated PL intensity of LED epitaxial wafers pre-annealed at 800°C in N2 ambient for 20 min and pre-annealed at 500°C in O2 ambient for 10 min. The inset shows the PL spectra of the two wafers. The integrated PL intensity of the wafers is the average value of 100 points measured from the entire 2-in. epitaxial layers. Assuming the integrated PL intensity of as-grown wafer is 100, the intensities of the wafers pre-annealed at 800°C and pre-annealed at 500°C are decreased to 83.4% and 99.2%, respectively. The obvious decrease in the integrated PL intensity of the wafer pre-annealed at 800°C is due to the increased non-radiative recombination that caused by the defects generated during the high-temperature thermal annealing process [11,19,20].Figure 1

Bottom Line: During the fabrication process, a 100-nm-thick indium tin oxide film was served as the p-type contact layer and annealed at 500°C in N2 ambient for 20 min to increase its transparency as well as to activate the p-type GaN.We discussed the mechanism of activation of p-type GaN at 500°C in N2 ambient.Furthermore, x-ray photoemission spectroscopy examinations were carried out to study the improved electrical performances of the LEDs without pre-activation of p-type GaN.

View Article: PubMed Central - PubMed

Affiliation: Engineering Research Center for Optoelectronics of Guangdong Province, School of Physics and Optoelectronics, South China University of Technology, Guangzhou, Guangdong 510640 China.

ABSTRACT
We fabricated GaN-based light-emitting diodes (LEDs) without pre-activation of p-type GaN. During the fabrication process, a 100-nm-thick indium tin oxide film was served as the p-type contact layer and annealed at 500°C in N2 ambient for 20 min to increase its transparency as well as to activate the p-type GaN. The electrical measurements showed that the LEDs were featured by a lower forward voltage and higher wall-plug efficiency in comparison with LEDs using pre-activation of p-type GaN. We discussed the mechanism of activation of p-type GaN at 500°C in N2 ambient. Furthermore, x-ray photoemission spectroscopy examinations were carried out to study the improved electrical performances of the LEDs without pre-activation of p-type GaN.

No MeSH data available.