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Influence of patterned sapphire substrates with different symmetry on the light output power of InGaN-based LEDs.

You YH, Su VC, Ho TE, Lin BW, Lee ML, Das A, Hsu WC, Kuan CH, Lin RM - Nanoscale Res Lett (2014)

Bottom Line: The GaN epitaxial layers grown on the hexagonal lattice arrangement PSS (HLAPSS) have a lower compressive strain than the ones grown on the square lattice arrangement PSS (SLAPSS).The quantum-confined Stark effect (QCSE) is also affected by the residual compressive strain.Based on the experimentally measured data and the ray tracing simulation results, the InGaN-based LED with the HLAPSS has a higher LOP than the one with the SLAPSS due to the weaker QCSE within multiple-quantum wells (MQWs).

View Article: PubMed Central - HTML - PubMed

Affiliation: Graduate Institute of Electronic Engineering and Department of Electrical Engineering, National Taiwan University, No. 1, Roosevelt Road Section 4, Daan District, Taipei 10617, Taiwan.

ABSTRACT
This paper aims to investigate the light output power (LOP) of InGaN-based light-emitting diodes (LEDs) grown on patterned sapphire substrates (PSSs) with different symmetry. The GaN epitaxial layers grown on the hexagonal lattice arrangement PSS (HLAPSS) have a lower compressive strain than the ones grown on the square lattice arrangement PSS (SLAPSS). The quantum-confined Stark effect (QCSE) is also affected by the residual compressive strain. Based on the experimentally measured data and the ray tracing simulation results, the InGaN-based LED with the HLAPSS has a higher LOP than the one with the SLAPSS due to the weaker QCSE within multiple-quantum wells (MQWs).

No MeSH data available.


Related in: MedlinePlus

The normalized EQE as a function of the forward current. The normalized EQE of InGaN-based LEDs grown on CSS, SLAPSS, and HLAPSS is plotted as a function of the forward current.
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Figure 7: The normalized EQE as a function of the forward current. The normalized EQE of InGaN-based LEDs grown on CSS, SLAPSS, and HLAPSS is plotted as a function of the forward current.

Mentions: Figure 7 reflects the associated normalized EQE versus the forward current of the InGaN-based LEDs having the CSS, SLAPSS, and HLAPSS. To prevent self-heating effect, the correlated efficiency droop of the devices was observed with the pulsed-mode measurement. The efficiency droop of the InGaN-based LEDs grown on the SLAPSS and HLAPSS are 64% and 60% at an injection current of 100 mA, respectively. The smaller efficiency droop is the result of the weaker QCSE within the MQWs from the use of HLAPSS. Furthermore, the InGaN-based LED grown on the CSS has the lowest efficiency droop, which is consistent with the previously discussed result of the smallest blueshift of the EL peak from the lower In composition of MQWs[25].


Influence of patterned sapphire substrates with different symmetry on the light output power of InGaN-based LEDs.

You YH, Su VC, Ho TE, Lin BW, Lee ML, Das A, Hsu WC, Kuan CH, Lin RM - Nanoscale Res Lett (2014)

The normalized EQE as a function of the forward current. The normalized EQE of InGaN-based LEDs grown on CSS, SLAPSS, and HLAPSS is plotted as a function of the forward current.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4225452&req=5

Figure 7: The normalized EQE as a function of the forward current. The normalized EQE of InGaN-based LEDs grown on CSS, SLAPSS, and HLAPSS is plotted as a function of the forward current.
Mentions: Figure 7 reflects the associated normalized EQE versus the forward current of the InGaN-based LEDs having the CSS, SLAPSS, and HLAPSS. To prevent self-heating effect, the correlated efficiency droop of the devices was observed with the pulsed-mode measurement. The efficiency droop of the InGaN-based LEDs grown on the SLAPSS and HLAPSS are 64% and 60% at an injection current of 100 mA, respectively. The smaller efficiency droop is the result of the weaker QCSE within the MQWs from the use of HLAPSS. Furthermore, the InGaN-based LED grown on the CSS has the lowest efficiency droop, which is consistent with the previously discussed result of the smallest blueshift of the EL peak from the lower In composition of MQWs[25].

Bottom Line: The GaN epitaxial layers grown on the hexagonal lattice arrangement PSS (HLAPSS) have a lower compressive strain than the ones grown on the square lattice arrangement PSS (SLAPSS).The quantum-confined Stark effect (QCSE) is also affected by the residual compressive strain.Based on the experimentally measured data and the ray tracing simulation results, the InGaN-based LED with the HLAPSS has a higher LOP than the one with the SLAPSS due to the weaker QCSE within multiple-quantum wells (MQWs).

View Article: PubMed Central - HTML - PubMed

Affiliation: Graduate Institute of Electronic Engineering and Department of Electrical Engineering, National Taiwan University, No. 1, Roosevelt Road Section 4, Daan District, Taipei 10617, Taiwan.

ABSTRACT
This paper aims to investigate the light output power (LOP) of InGaN-based light-emitting diodes (LEDs) grown on patterned sapphire substrates (PSSs) with different symmetry. The GaN epitaxial layers grown on the hexagonal lattice arrangement PSS (HLAPSS) have a lower compressive strain than the ones grown on the square lattice arrangement PSS (SLAPSS). The quantum-confined Stark effect (QCSE) is also affected by the residual compressive strain. Based on the experimentally measured data and the ray tracing simulation results, the InGaN-based LED with the HLAPSS has a higher LOP than the one with the SLAPSS due to the weaker QCSE within multiple-quantum wells (MQWs).

No MeSH data available.


Related in: MedlinePlus