Room-temperature CW operation of a nitride-based vertical-cavity surface-emitting laser using thick GaInN quantum wells

Furuta, Takahisa; Matsui, Kunihiko; Horikawa, Kosuke; Ikeyama, Kazuki; Kozuka, Yugo; Yoshida, Shigeo; Akagi, Takanobu; Takeuchi, Tetsuya; Kamiyama, Satoshi; Iwaya, Motoaki; Akasaki, Isamu

doi:10.7567/jjap.55.05fj11

Cited by 45 publications

(27 citation statements)

References 24 publications

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“…In Figure 2a, the thickness of the SiO 2 layer was 100 nm with an aperture diameter of 8 µm. A 20 nm ITO contact layer was deposited following fabrication of the conventional SiO 2 aperture, following which a 10.5-pair SiO 2 /Nb 2 O 5 DBR and a 38 nm Nb 2 O 5 spacer layer were applied to the ITO such that a VCSEL cavity was obtained [11]. Assuming that a local shift of the resonance wavelength produces a corresponding change in the effective index [24], a calculation of the resonance wavelength difference gave a normalized effective index difference (∆n eff /n) of −0.025 for this structure, thus showing anti-guiding.…”

Section: Enhancement Of Differential Quantum Efficiencymentioning

confidence: 99%

“…Based on these requirements, a combination of blue VCSELs and phosphors are the most attractive light source for next-generation laser headlamps. Recently, some research groups have achieved continuous-wave (CW) operation of GaN-based VCSELs [3][4][5][6][7][8][9][10][11] and reported output power values of approximately 1 mW [7,10,[12][13][14] and 4.2 mW [15]. However, further improvements in GaN-based VCSELs are required for applications such as laser headlamps.…”

Section: Introductionmentioning

confidence: 99%

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High-Power GaN-Based Vertical-Cavity Surface-Emitting Lasers with AlInN/GaN Distributed Bragg Reflectors

et al. 2019

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High-efficiency and high-power operation have been demonstrated for blue GaN-based vertical-cavity surface-emitting lasers (VCSELs) with AlInN/GaN distributed Bragg reflectors. The high-efficiency performance was achieved by introducing a novel SiO2-buried lateral index guide and adjusting the front mirror reflectivity. Lateral optical confinement has been shown to greatly lower the otherwise significant loss of transverse radiation exhibited by typical VCSELs based on GaN. Employing a long (10λ) cavity can also enhance the output power, by lowering the thermal resistance of the VCSEL and increasing the operating current associated with thermal rollover. This modification, in conjunction with optimized front mirror reflectivity and a buried SiO2 lateral index guide, results in a blue VCSEL (in the continuous wave mode with an 8 μm aperture at 20 °C) having a superior differential quantum efficiency value of 31% and an enhanced 15.7 mW output power. This unit also exhibits a relatively high output power of 2.7 mW at temperatures as high as 110 °C. Finally, a 5.5 μm aperture VCSEL was found to generate a narrow divergence (5.1°) single-lobe far field pattern when operating at an output power of approximately 5 mW.

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Section: Enhancement Of Differential Quantum Efficiencymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High-Power GaN-Based Vertical-Cavity Surface-Emitting Lasers with AlInN/GaN Distributed Bragg Reflectors

et al. 2019

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“…[1][2][3] In particular, III-nitride VCSELs have attracted much interest owing to their unique emission wavelengths (ultraviolet to green) for attractive applications, such as visible light communication, optical sensors, displays, and atomic clocks. [4][5][6][7][8][9] Reports of III-nitride VCSELs have consisted of hybrid epitaxial=dielectric 10,11) and dual dielectric DBR designs. [7][8][9][12][13][14] Both designs have required intracavity contacts, and indium tin oxide (ITO) has been the most commonly used material to improve lateral current spreading on the p-side.…”

Section: ++mentioning

confidence: 99%

GaN-based vertical-cavity surface-emitting lasers with tunnel junction contacts grown by metal-organic chemical vapor deposition

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Forman

Lee

et al. 2018

Appl. Phys. Express

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We report the first demonstration of III-nitride vertical-cavity surface-emitting lasers (VCSELs) with tunnel junction (TJ) intracavity contacts grown completely by metal-organic chemical vapor deposition (MOCVD). For the TJs, n ++ -GaN was grown on in-situ activated p ++ -GaN after buffered HF surface treatment. The electrical properties and epitaxial morphologies of the TJs were first investigated on TJ LED test samples. A VCSEL with a TJ intracavity contact showed a lasing wavelength of 408 nm, a threshold current of >15 mA (10 kA/cm 2 ), a threshold voltage of 7.8 V, a maximum output power of 319 µW, and a differential efficiency of 0.28%.

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“…Al 0.82 In 0.18 N/GaN is a lattice-matched alternative but also suffers from a small index contrast. Despite these challenges, crack-free and high reflectivity DBRs using both AlN/GaN 3,8,14,15 and AlInN/GaN 6,11,16,17 have been successfully grown and used as n-side DBRs in III-nitride VCSELs.…”

Section: Introductionmentioning

confidence: 99%

Electrically conductive ZnO/GaN distributed Bragg reflectors grown by hybrid plasma-assisted molecular beam epitaxy

et al. 2017

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III-nitride-based vertical-cavity surface-emitting lasers have so far used intracavity contacting schemes since electrically conductive distributed Bragg reflectors (DBRs) have been difficult to achieve. A promising material combination for conductive DBRs is ZnO/GaN due to the small conduction band offset and ease of n-type doping. In addition, this combination offers a small lattice mismatch and high refractive index contrast, which could yield a mirror with a broad stopband and a high peak reflectivity using less than 20 DBR-pairs. A crack-free ZnO/GaN DBR was grown by hybrid plasma-assisted molecular beam epitaxy. The ZnO layers were approximately 20 nm thick and had an electron concentration of 1×10 19 cm −3 , while the GaN layers were 80-110 nm thick with an electron concentration of 1.8×10 18 cm −3. In order to measure the resistance, mesa structures were formed by dry etching through the top 3 DBR-pairs and depositing non-annealed Al contacts on the GaN-layers at the top and next to the mesas. The measured specific series resistance was dominated by the lateral and contact contributions and gave an upper limit of ∼10 −3 Ω cm 2 for the vertical resistance. Simulations show that the ZnO electron concentration and the cancellation of piezoelectric and spontaneous polarization in strained ZnO have a large impact on the vertical resistance and that it could be orders of magnitudes lower than what was measured. This is the first report on electrically conductive ZnO/GaN DBRs and the upper limit of the resistance reported here is close to the lowest values reported for III-nitride-based DBRs.

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Room-temperature CW operation of a nitride-based vertical-cavity surface-emitting laser using thick GaInN quantum wells

Cited by 45 publications

References 24 publications

High-Power GaN-Based Vertical-Cavity Surface-Emitting Lasers with AlInN/GaN Distributed Bragg Reflectors

High-Power GaN-Based Vertical-Cavity Surface-Emitting Lasers with AlInN/GaN Distributed Bragg Reflectors

GaN-based vertical-cavity surface-emitting lasers with tunnel junction contacts grown by metal-organic chemical vapor deposition

Electrically conductive ZnO/GaN distributed Bragg reflectors grown by hybrid plasma-assisted molecular beam epitaxy

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