Room-Temperature Low-Threshold Surface-Stimulated Emission by Optical Pumping from Al<sub>0.1</sub>Ga<sub>0.9</sub>N/GaN Double Heterostructure

Amano, Hiroshi; Watanabe, Nobuaki; Koide, Norikatsu; Akasaki, Isamu

doi:10.1143/jjap.32.l1000

Cited by 116 publications

(33 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The expected increase of the index of refraction with increasing photon energy towards the bandgap, and the overall decrease with Al content, is observed for the whole series of samples. The dependence of refractive index on energy obtained for the GaN and the Al 0.1 Ga 0.9 N samples is in excellent agreement with the results of Amano et al [19], [20] and Vidal et al [21]. For 0.7 < x < 1 there is a tendency for the experimentally determined refractive indexes to be too low, most probably due to a decrease of the effective film density compared to an ideal crystal.…”

Section: Index Of Refractionsupporting

confidence: 89%

AlGaN-Based Bragg Reflectors

Ambacher

Arzberger

Brunner

et al. 1997

MRS Internet j. nitride semicond. res.

View full text Add to dashboard Cite

We have studied the dependence of the absorption edge and the refractive index of wurtzite Al x Ga 1-x N films on composition using transmission, ellipsometry and photothermal deflection spectroscopy. The Al molar fraction of the Al x Ga 1-x N films grown by plasma-induced molecular beam epitaxy was varied through the entire range of composition (0 ≤ x ≤ 1). We determined the absorption edges of Al x Ga 1-x N films and a bowing parameter of 1.3 ± 0.2 eV. The refractive index below the bandgap was deduced from the interference fringes, the dielectric function between 2.5 and 25 eV from ellipsometry measurements. The measured absorption coefficients and refractive indices were used to calculate the design and reflectivity of AlGaN-based Bragg reflectors working in the blue and near-ultraviolet spectral region.

show abstract

Section: Index Of Refractionsupporting

confidence: 89%

AlGaN-Based Bragg Reflectors

Ambacher

Arzberger

Brunner

et al. 1997

MRS Internet j. nitride semicond. res.

View full text Add to dashboard Cite

show abstract

“…Refractive indices of AlN and GaN were also determined, by the same technique, to be 2.46 and 2.72 at 250 nm and 370 nm, respectively, where the refractive index of the 6H-SiC substrate was assumed to be 3.28 at 250 nm and 2.81 at 370 nm [17]. These values are very close to those in previous reports [18,19]. Experimental results indicate that the refractive indices of BAlN and BGaN strongly depend on the boron content and change drastically by introducing a small amount of boron.…”

Section: Resultssupporting

confidence: 82%

Refractive indices of B _x Al _{1−
x} N ( x = 0–0.012) and B _y Ga _{1−
y} N ( y = 0–0.023) epitaxial layers in ultraviolet region

Watanabe

Takano

Jinen

et al. 2003

phys. stat. sol. (c)

View full text Add to dashboard Cite

PACS 81.05. Ea, 81.15.Kk Refractive indices of B x Al 1-x N and B y Ga 1-y N epitaxial layers were determined in the ultraviolet (UV) wavelength range from 230 nm to 600 nm by the light reflectance spectrum. The relative refractive index differences of (AlN/B 0.01 Al 0.99 N) and (GaN/B 0.02 Ga 0.98 N) heterostructures were 17% at 250 nm and 11% at 370 nm, respectively. These values indicate that an optical waveguide can be organized in the UV to deep-UV spectral region using the nitride semiconductors which include a small amount of boron. The relative refractive index difference of 6% was achieved with only 0.2% and 1.1% of boron for (AlN/B x Al 1-x N) and (GaN/B y Ga 1-y N) heterostructures at 250 nm and 370 nm, respectively. 1 Introduction Recent studies on light-emitting devices focus on high-power and highly efficient UVlight-emitting diodes and laser diodes. However power exchange efficiency from electrical to optical power must be improved in the UV-light-emitting devices. The reasons for this small power exchange efficiency was believed to be related to the crystal quality, for example, residual strain and large amount of dislocation density in the epitaxial layer. The residual strain originates from thermal strain and lattice mismatch in heterostructure. The thermal stress is caused by the difference of thermal expansion coefficients. A (GaN/AlN) multi-buffer-layer structure was proposed as a residual-strain-controlling technique in the GaN and AlN grown on a SiC substrate [1][2][3].The BAlGaN quaternary system was suggested as a new lattice-matched system to the SiC and AlN substrates [4]. Estimated band-gap energy (Eg) of the BAlGaN quaternary system are between 6.3 eV (190 nm for the B 0.05 Al 0.95 N) and 3.8 eV (340 nm for the B 0.17 Ga 0.83 N) [4]. Therefore, this quaternary system is a promising material for the light-emitting devices of the UV to deep-UV spectral region.Possible epitaxial growth of the BAlN ternary and the BN binary system were first demonstrated on the 6H-SiC substrate by low-pressure metalorganic vapor phase epitaxy (LP-MOVPE) [4]. Epitaxial growth of BGaN was demonstrated by molecular beam epitaxy (MBE) and VPE [5,6]. The maximum boron contents up to 13% and 9% were experimentally demonstrated for BAlN and BGaN, respectively. The maximum boron contents are sufficient to lattice-match the BAlGaN quaternary system to AlN [7]. The first photoluminescence (PL) emission from BGaN was demonstrated at a low temperature [8]. The bandoffset and refractive indices of BGaN and BAlGaN, and the band-gap energy, effective mass, and optical gain of BGaN were estimated theoretically [9][10][11]. Room-temperature PL emission from the (BGaN/AlGaN) multi-quantum-well (MQW) structure was first reported at 360.4 nm [12]. Then, improved PL intensity and characteristics of the strain-controlled (BAlGaN/AlN) MQW structure were also reported at 250.0 nm by adopting the (GaN/AlN) multi-buffer-layer structure [13,14]. However, there is no experimental data on the refractive indices of BAlN and BGaN.

show abstract

“…when the photon energy is smaller than the band gap of AlGaN, interference oscillation in the thick GaN layer is seen for both samples. At around 312 nm, a peak from the thin AlGaN layer is seen [3], and sample B shows a higher peak than sample A. The spectra did not change upon annealing.…”

Section: Resultsmentioning

confidence: 90%

Thermal Stability of Sheet Resistance in AlGaN/GaN 2DEG Structure

Shiojima

Shigekawa

2002

phys. stat. sol. (c)

View full text Add to dashboard Cite

PACS 73.40.Kp An annealing study of an AlGaN/GaN two-dimensional electron gas structure was conducted in combination with precise AlGaN thickness measurements using reflectivity spectra. It is found that the sheet resistance increases when annealing is performed below the growth temperature, and the increase depends on the AlGaN thickness and crystal quality. One possible explanation for the increase is that Si donors in low-quality AlGaN layers are passivated or compensated from the top surfaces upon annealing.Introduction For high-power and high-frequency applications of electron devices, the growth of an AlGaN/GaN two-dimensional electron gas (2DEG) structure with a higher electron mobility (m) and larger carrier density has been investigated [1]. In the actual FET process, a high-temperature anneal is required in order to form Ti/Al ohmic contacts ($800 C) [2], so the thermal stability of the thin AlGaN layer and 2DEG structure is very important. This paper discusses the annealing temperature dependence of sheet resistance (R s ) in conjunction with precise AlGaN thickness measurements. We found that R s increases when annealing is performed below the growth temperature, and the increase depends on the AlGaN thickness and crystal quality.

show abstract

Room-Temperature Low-Threshold Surface-Stimulated Emission by Optical Pumping from Al_0.1Ga_0.9N/GaN Double Heterostructure

Cited by 116 publications

References 11 publications

AlGaN-Based Bragg Reflectors

AlGaN-Based Bragg Reflectors

Refractive indices of B _x Al _{1−
x} N ( x = 0–0.012) and B _y Ga _{1−
y} N ( y = 0–0.023) epitaxial layers in ultraviolet region

Thermal Stability of Sheet Resistance in AlGaN/GaN 2DEG Structure

Contact Info

Product

Resources

About

Room-Temperature Low-Threshold Surface-Stimulated Emission by Optical Pumping from Al0.1Ga0.9N/GaN Double Heterostructure

Cited by 116 publications

References 11 publications

AlGaN-Based Bragg Reflectors

AlGaN-Based Bragg Reflectors

Refractive indices of B x Al 1− x N ( x = 0–0.012) and B y Ga 1− y N ( y = 0–0.023) epitaxial layers in ultraviolet region

Thermal Stability of Sheet Resistance in AlGaN/GaN 2DEG Structure

Contact Info

Product

Resources

About

Room-Temperature Low-Threshold Surface-Stimulated Emission by Optical Pumping from Al_0.1Ga_0.9N/GaN Double Heterostructure

Refractive indices of B _x Al _{1−
x} N ( x = 0–0.012) and B _y Ga _{1−
y} N ( y = 0–0.023) epitaxial layers in ultraviolet region