High-efficiency 269 nm emission deep ultraviolet light-emitting diodes

Adivarahan, V.; Wu, S.; Zhang, J. P.; Chitnis, A.; Shatalov, M.; Mandavilli, V.; Gaška, R.; Khan, M. Asif

doi:10.1063/1.1756202

Cited by 121 publications

(76 citation statements)

References 10 publications

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“…Milliwatt class, III-Nitride-based, ultraviolet light emitting diodes (UVLEDs) have been fabricated that operate at wavelengths between 250 nm and 365 nm. 1 However, a limitation of these devices is the presence of a large number of defects that arise from heteroepitaxial growth on sapphire substrates that result in reduced output efficiency and lifetimes while contributing to overheating. Similar difficulties were encountered during the development of InGaNbased blue/green emitters.…”

Section: Introductionmentioning

confidence: 99%

Growth of AlGaN alloys exhibiting enhanced luminescence efficiency

Sampath

Garrett

Collins

et al. 2006

J. Electron. Mater.

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Interest in developing ultraviolet emitters using the III-Nitride family of semiconductors has sparked considerable effort in fabricating AlGaN alloys that exhibit enhanced luminescence based on strong carrier localization, similar to their InGaN brethren. In this paper, we report on the growth of such alloys by plasma-assisted molecular beam epitaxy (PA-MBE) without the use of indium. This enhancement is attributed to the presence of nanoscale compositional inhomogeneities (NCIs) in these materials. The emission wavelength in these materials has been tuned between 275 nm and 340 nm by varying growth conditions. The effects of dislocations on double heterostructures (DHs) that employ an NCI AlGaN active region has been investigated, with an internal quantum efficiency as high as 32% obtained for the lowest dislocation density samples (3 3 10 10 cm ÿ2 ). Prototype DH-ultraviolet light emitting diodes (DH-UVLEDs) emitting at 324 nm were fabricated employing an NCI AlGaN alloy as the active region.

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Section: Introductionmentioning

confidence: 99%

Growth of AlGaN alloys exhibiting enhanced luminescence efficiency

Sampath

Garrett

Collins

et al. 2006

J. Electron. Mater.

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“…Group III-nitride wide-band-gap semiconductors have been recognized as leading materials not only for high temperature and high power microelectronic devices [1][2][3][4][5] but also for many optoelectronic devices [6][7][8][9][10][11][12], such as light-emitting diodes (LEDs) and laser diodes (LDs). One of the frontiers of LED development is the application of AlGaN alloys to enable LEDs emitting at deep ultraviolet (UV) wavelengths (l < 300 nm).…”

Section: Introductionmentioning

confidence: 99%

Structural and optical properties of Al x Ga1 − x N/Al y Ga1 − y N multiple quantum wells for deep ultraviolet emission

Wang

et al. 2009

Front. Optoelectron. China

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The Al x Ga 1 -x N/Al y Ga 1 -y N multiple quantum well (MQW) structure for deep ultraviolet emission has been grown on sapphire by metal organic chemical vapor deposition (MOCVD). High resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), and cathodoluminescence (CL) are used to characterize the structural and optical properties of MQWs, respectively. Clear step flows can be observed in the AFM image indicating a two-dimensional growth model. There are many cracks on the surface of the MQW structure because of the high tensile stress. HRXRD shows multiple satellite peaks to the 2nd order. The HRXRD simulation shows that the MQW period is about 11.5 nm. The emission peak of Al x Ga 1 -x N/Al y Ga 1 -y N MQWs is about 295 nm in the deep ultraviolet region from the CL spectra.

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“…To date all the reported III-nitride UV LEDs have employed either basal plane sapphire or (0001) SiC substrates [1][2][3]. III-N quantum well (QW) structures grown over conventional (0001) orientation are subjected to significant quantum-confined Stark effect (QCSE) caused by strong polarization fields.…”

mentioning

confidence: 99%

Influence of stacking faults on the properties of GaN‐based UV light‐emitting diodes grown on non‐polar substrates

Chen

Adivarahan

Shatalov

et al. 2005

phys. stat. sol. (c)

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We report on the reduction of defect densities in non-polar a-plane GaN films over r-plane sapphire achieved by epitaxial laterally overgrowth (ELOG) approach. A mask pattern was used to produce ELOG GaN with wing region width of about 30µm. Based on transmission electron microscopy (TEM) results, the window regions have stacking faults density of ∼10 6 cm -1 and threading dislocation density of ∼10 10 cm -2 . Both ELOG Ga-face and N-face wing regions have stacking fault density of ~10 5 cm -1 , and dislocation density less than 10 8 cm -2. Cathodoluminescence studies reveal the difference in defect densities between N-faced and Ga-faced wings. GaN-based UV light-emitting diode formed on Ga-faced wing shows stronger quantum well emission and weaker parasitic emission than that formed on N-faced wing. . III-N quantum well (QW) structures grown over conventional (0001) orientation are subjected to significant quantum-confined Stark effect (QCSE) caused by strong polarization fields. The QCSE results in carrier separation because of band bending, thereby reducing device efficiency of light emitting devices [4,5]. Recently, several groups including ours have reported the growth of non-polar (11-20) plane GaN films over (1-102) r-plane sapphire substrates. It has been demonstrated that a-plane QW structures grown over r-plane sapphires are free from polarization-induced internal electrostatic field [6][7][8][9]. Thus, there has been considerable interest in the growth of high quality nitride films and heterostructures with non-polar orientations for the development of high efficiency light emitters.

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High-efficiency 269 nm emission deep ultraviolet light-emitting diodes

Cited by 121 publications

References 10 publications

Growth of AlGaN alloys exhibiting enhanced luminescence efficiency

Growth of AlGaN alloys exhibiting enhanced luminescence efficiency

Structural and optical properties of Al x Ga1 − x N/Al y Ga1 − y N multiple quantum wells for deep ultraviolet emission

Influence of stacking faults on the properties of GaN‐based UV light‐emitting diodes grown on non‐polar substrates

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