Suppressed quantum-confined Stark effect in InGaN-based LEDs with nano-sized patterned sapphire substrates

Su, Vin‐Cent; Chen, Po-Hsun; Lin, Ray-Ming; Lee, Ming-Lun; You, Yao-Hong; Ho, Chung-I; Chen, Yi-Chi; Chen, Wei-Fan; Kuan, Chieh-Hsiung

doi:10.1364/oe.21.030065

Cited by 43 publications

(17 citation statements)

References 31 publications

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“…The first zone lies between 50 °C and 70 °C, where a blue shift of the main peak from 593 nm to 585 nm takes place. This result may be attributed to the suppression of the quantum confinement Stark effect [40]. The second zone lies between 70 °C and 170 °C, where the main peak displays a steady red shift from 585 nm to 593 nm which is caused by the lattice expansion and vibration [41].…”

Section: Resultsmentioning

confidence: 99%

Phosphor-Free InGaN White Light Emitting Diodes Using Flip-Chip Technology

Chang

Chen

et al. 2017

Materials

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Monolithic phosphor-free two-color gallium nitride (GaN)-based white light emitting diodes (LED) have the potential to replace current phosphor-based GaN white LEDs due to their low cost and long life cycle. Unfortunately, the growth of high indium content indium gallium nitride (InGaN)/GaN quantum dot and reported LED’s color rendering index (CRI) are still problematic. Here, we use flip-chip technology to fabricate an upside down monolithic two-color phosphor-free LED with four grown layers of high indium quantum dots on top of the three grown layers of lower indium quantum wells separated by a GaN tunneling barrier layer. The photoluminescence (PL) and electroluminescence (EL) spectra of this white LED reveal a broad spectrum ranging from 475 to 675 nm which is close to an ideal white-light source. The corresponding color temperature and color rendering index (CRI) of the fabricated white LED, operated at 350, 500, and 750 mA, are comparable to that of the conventional phosphor-based LEDs. Insights of the epitaxial structure and the transport mechanism were revealed through the TEM and temperature dependent PL and EL measurements. Our results show true potential in the Epi-ready GaN white LEDs for future solid state lighting applications.

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Section: Resultsmentioning

confidence: 99%

Phosphor-Free InGaN White Light Emitting Diodes Using Flip-Chip Technology

Chang

Chen

et al. 2017

Materials

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“…Based on the previous study published by our group [23], the smaller residual compressive strain can result in a weaker quantum-confined Stark effect (QCSE) in MQWs, which enhanced the LOP of InGaN-based LEDs. Therefore, the effect of InGaN-based LEDs having the PSSs with different symmetry on the QCSE was further elucidated by utilizing the excitation current-dependent electroluminescence (EL) measurement.…”

Section: Methodsmentioning

confidence: 99%

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

You

et al. 2014

Nanoscale Res Lett

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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).

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“…This improvement can be attributed to the increase in radiative efficiency of the material. The growths of GaN materials on nano-sized PSSs have resulted in 2-order of magnitude reduction in TDs in GaN thin film, which has been applied to achieve improved IQE in LEDs [10][11][12].…”

Section: Introductionmentioning

confidence: 99%