AlGaN-based laser diodes for the short-wavelength ultraviolet region

Yoshida, Harumasa; Kuwabara, Masakazu; Yamashita, Yoshifumi; Takagi, Yasufumi; Uchiyama, Keisuke; Kan, Hirofumi

doi:10.1088/1367-2630/11/12/125013

Cited by 63 publications

(37 citation statements)

References 31 publications

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“…The dislocation density of crack-free AlGaN was observed between 1.8-6.0 × 10 8 /cm 2 from cathodoluminescence (CL) dark spots [9]. From these results of low dislocation AlGaN grown on inclined GaN facet, the various UV-LDs between 336-360 nm with AlGaN/AlGaN or GaN/AlGaN MQWs were demonstrated [9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 83%

Stimulated Emission with 349-nm Wavelength in GaN/AlGaN MQWs by Optical Pumping

Kim

Bae

et al. 2017

Appl. Sci. Converg. Technol.

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The crack-free AlGaN template has been successfully grown by using selective area growth with triangular GaN facet. The triangular GaN stripe structure was obtained by vertical growth rate enhanced mode with low growth temperature of 950 o C and high growth pressure of 500 torr. The lateral growth rate enhanced mode of AlGaN for crackfree and flat surface was also investigated. Low pressure of 30 torr and high V/III ratio of 4400 were favorable for lateral growth of AlGaN. It was confirmed that the 4 μm -thick Al 0.2 Ga 0.8 N was crack-free over entire 2-inch wafer. The dislocation density of Al 0.2 Ga 0.8 N was as low as ~7.6 × 10 8 /cm 2 measured by cathodoluminescence. Based on the high quality AlGaN with low dislocation density, the ultraviolet laser diode epitaxy with cladding, waveguide and GaN/ AlGaN multiple quantum well (MQW) was grown by metalorganic chemical vapor deposition. The stimulated emission at 349 nm with full width at half maximum of 1.8 nm from the MQW was observed through optical pumping experiment with 193 nm KrF laser. We also have fabricated the deep ridge type ultraviolet laser diode (UV-LD) with 5 μm-wide and 700 μm-long cavity for electrical properties. The turn on voltage was below 5 V and the resistance was55 Ω at applied voltage of 10 V. The amplified spontaneous emission spectrum of UV-LD was also observed from pulsed current injection.

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Section: Introductionmentioning

confidence: 83%

Stimulated Emission with 349-nm Wavelength in GaN/AlGaN MQWs by Optical Pumping

Kim

Bae

et al. 2017

Appl. Sci. Converg. Technol.

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“…In contrast to visible LEDs and lasers [1][2][3][4][5], the realization of electrically-injected mid-(O ~250-320nm) and deep-ultraviolet (UV) (O ~220-250nm) AlGaN quantum wells (QWs) lasers [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] have been limited to emission wavelength (O ~320-360nm [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], while only optically-pumped deep UV lasers had been realized [15]. The challenges in achieving electricallyinjected mid-and deep-UV AlGaN QWs lasers are attributed to: 1) the growth challenges in obtaining high quality pAlN and high Al-content AlGaN gain media, and 2) the lack of understanding on the gain properties of deep UV AlGaN QWs.…”

Section: Introductionmentioning

confidence: 99%

Engineering of AlGaN-Delta-GaN quantum wells gain media for mid- and deep-ultraviolet lasers

2012

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The gain characteristics of AlGaN-delta-GaN QWs active region with varying delta-GaN positions and AlGaN compositions are analyzed. From our finding, the use of AlGaN-delta-GaN QW resulted in ~ 7-times increase in material gain, in comparison to that of conventional AlGaN QW, for gain media emitting at 240 nm. By employing asymmetric QW design, with optimized GaN delta layer position and asymmetric AlGaN composition layers, the optimized optical gain can be achievable for AlGaN-delta-GaN QW structure with realistic design applicable for deep and mid UV lasers.

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“…To alleviate this problem, overgrowth techniques involving ex situ patterning of an epitaxial layer have been attempted. 5,6 In addition to reduced dislocation density in the overgrown regions, these techniques effectively disconnect the upper AlGaN layer from the preceding layers. This allows growth of thick, crack-free layers.…”

Section: Introductionmentioning

confidence: 99%

Structural Characterization of Highly Conducting AlGaN (x > 50%) for Deep-Ultraviolet Light-Emitting Diode

Dion

Fareed

Zhang

et al. 2011

Journal of Elec Materi

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Off-axis reciprocal-space mapping was performed on aluminum gallium nitride deep-ultraviolet light-emitting diode base layers. The results indicate that aluminum gallium nitride films growing on aluminum nitride-on-sapphire templates initially grow in compression, nearly lattice matched to the relaxed aluminum nitride buffer layer with approximately 0.5% biaxial strain. This compressive strain may be partially relieved over the course of the thick aluminum gallium nitride growth when a high-quality aluminum nitride and superlattice layer is used. Additionally, a growth interruption appears to allow growth of an unstrained aluminum gallium nitride layer without a gradual release of compressive strain. Growth on a bulk aluminum nitride substrate appears to yield an aluminum gallium nitride layer in tension rather than compression.

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AlGaN-based laser diodes for the short-wavelength ultraviolet region

Cited by 63 publications

References 31 publications

Stimulated Emission with 349-nm Wavelength in GaN/AlGaN MQWs by Optical Pumping

Stimulated Emission with 349-nm Wavelength in GaN/AlGaN MQWs by Optical Pumping

Engineering of AlGaN-Delta-GaN quantum wells gain media for mid- and deep-ultraviolet lasers

Structural Characterization of Highly Conducting AlGaN (x > 50%) for Deep-Ultraviolet Light-Emitting Diode

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