Optical and structural properties of BGaN layers grown on different substrates

Kadys, A.; Mickevičius, J.; Malinauskas, T.; Jurkevičius, Jonas; Kolenda, M.; Stanionytė, Sandra; Dobrovolskas, D.; Тамулайтис, Г.

doi:10.1088/0022-3727/48/46/465307

Cited by 24 publications

(13 citation statements)

References 21 publications

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“…However, if we also define the BN gap as the energy difference between the BN states most closely resembling the edge states of AlN (13.9 eV) we obtain a bowing parameter (b BN-AlN =8.7 eV) in good agreement with Shen et al 36) Our b BN-GaN value is higher than calculated by Said et al 37) and estimated by the experimental review of Kadys et al, 38) but lower than the range calculated by Jiang et al 39) Since gallium content controls the band gap in the relevant composition range of these alloys, knowledge of experimental AlGaN band gaps allows for easy selection of BAlGaN alloys with the same band gap, although corrections need to be applied for the band-gap shift due to strain in epitaxially strained layers.…”

supporting

confidence: 89%

“…Our calculations show that the partial substitution of aluminum with boron in Ga x Al 1-x N alloys does not significantly change the band gap for these low boron concentrations. Figure 3 shows the calculated band gap vs. Ga fraction x for Al 1-x 37) and estimated by the experimental review of Kadys et al, 38) but lower than the range calculated by Jiang et al 39) Since gallium content controls the band gap in the relevant composition range of these alloys, knowledge of experimental AlGaN band gaps allows for easy selection of BAlGaN alloys with the same band gap, although corrections need to be applied for the band-gap shift due to strain in epitaxially strained layers.…”

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confidence: 94%

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BAlGaN alloys nearly lattice-matched to AlN for efficient UV LEDs

Williams

Kioupakis

2019

Applied Physics Letters

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The lattice mismatch between AlGaN and AlN substrates limits the design and efficiency of UV LEDs, but it can be mitigated by the co-incorporation of boron. We employ hybrid density functional theory to investigate the thermodynamic, structural, and electronic properties of BAlGaN alloys. We show that BAlGaN can lattice match AlN with band gaps that match AlGaN of the same gallium content. We predict that BAlGaN emits transverse-electric polarized for gallium content of ~45% or more. Our results indicate that BAlGaN alloys are promising materials for higher efficiency UV optoelectronic devices on bulk AlN substrates. Main TextThe efficient generation of UV light is useful in many technological applications, including sensing and measurement of inks and markers, protein analysis and DNA sequencing, UV curing of resins and solvent-free printer ink, and, most importantly, disinfection and sterilization. 1,2) AlGaN-based LEDs are the most promising semiconducting UV generation technology due to their wide emission spectrum range (from 6.2 eV for AlN to 3.4 eV for GaN), relatively high-efficiency emission of light, ability to be doped n-and p-type, robust mechanical properties, and lack of toxic elements. 2) Current UV generation technology uses mercury-based lamps, 3) but the Minamata Convention on Mercury 4) has over 100 nations pledged to phase out mercury-based technologies.However, the efficiency of AlGaN-based UV LEDs is still hampered by multiple material issues. Of note, light extraction becomes less efficient for high Al-content LEDs, as the polarization of emitted light switches from transverse electric (TE) (emitted preferentially along the c direction) to transverse magnetic (TM) polarization (emitted preferentially within the c-plane) above 68% Al for 3 nm Al x Ga 1-x N quantum wells. 5,6)

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confidence: 89%

mentioning

confidence: 94%

BAlGaN alloys nearly lattice-matched to AlN for efficient UV LEDs

Williams

Kioupakis

2019

Applied Physics Letters

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“…A similar trend was observed previously and was attributed to the increasing number of defects. 8,16 Furthermore, the defect-to bandgap-related emission intensity ratio increases with increasing boron content as shown in Fig. 4(c).…”

Section: Resultsmentioning

confidence: 79%

“…It is in accordance with previous reports for photoluminescence studies. 8,16,17 For all samples, the photoluminescence signal associated with near band edge emission is present; however, it deteriorates with increasing B content. A similar trend was observed previously and was attributed to the increasing number of defects.…”

Section: Resultsmentioning

confidence: 94%

“…[11][12][13] It was also shown that BGaN exhibits a similar optical gain to GaN. 14 However, for wurtzite phase BGaN, the influence of boron on the bandgap of the alloy is not evident, 15 since theoretical works predict blueshift of the bandgap, 13 while experimental results show the opposite trend 8,16,17 for samples with boron content up to 5.5%. This discrepancy may be explained by alloy fluctuations in experimentally examined samples and computational limitations concerning the simulation of low boron contents.…”

Section: Introductionmentioning

confidence: 99%

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Boron influence on bandgap and photoluminescence in BGaN grown on AlN

Zdanowicz

Iida

Pawlaczyk

et al. 2020

Journal of Applied Physics

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Since the BGaN alloy is considered a promising material in the wide range of optoelectronic applications, a detailed study of its band structure and optical properties is highly demanded. Here, B x Ga 1Àx N layers with 0.5%, 1.1%, and 1.2% B were grown by metalorganic vapor-phase epitaxy on AlN/sapphire templates and investigated by structural and optical methods. The bandgaps of the investigated alloys were examined by contactless electroreflectance (CER) spectroscopy. Because no GaN layer is present in the investigated samples, the detected CER resonances do not overlap with the GaN-related signal, which is typical for BGaN layers grown on GaN templates. Thus, the energy of the bandgap-related transition in BGaN samples can be unambiguously determined from the resonances observed in the CER spectra. The boron-induced redshift of the bandgap was determined to be about 60 meV/% B for the studied samples. By means of photoluminescence measurements, the deteriorating optical quality of samples with increasing boron content is shown as the decreasing bandgapto defect-related emission intensity ratio. What is more, the defect-related emission is shifted from typical for GaN yellow range to the red and is located at 1.9 eV for all BGaN samples.

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Effect of Film Thickness on Structural Stability for BAlN and BGaN Alloys: Bond‐Order Interatomic Potential Calculations

Hasegawa

Akiyama

Pradipto

et al. 2020

Physica Status Solidi (b)

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The effects of film thickness on the relative stability among 5-fold coordinated hexagonal, 4-fold coordinated wurtzite and zinc blende structures in BAlN and BGaN alloys are theoretically investigated based on empirical bond-order potential calculations. It is revealed that the trend of stable structure in BAlN alloys is different from that of BGaN alloys. The film thickness for the stabilization of the hexagonal structure increases with boron composition x for B x Ga 1-x N alloys, while the thickness decreases for B x Al 1-x N alloys. The difference in the stabilization of the hexagonal structure between B x Al 1-x N and B x Ga 1-x N alloys is due to the inhibition of in-plane lattice relaxation in B x Al 1-x N alloys. These results suggest that our approach using the bond-order potential is feasible to investigate the stability of alloy systems with not only tetrahedrally coordinated forms such as the wurtzite and zinc blende structures but also specific forms containing the 5-fold coordinated hexagonal structure. IntroductionTwo-dimensional (2D) atomic layer materials such as graphene, [1] transition metal dichalcogenides, [2] and hexagonal (Hex) structured boron nitride have currently been paid much attention for applications in nanodevices. As a dielectric substrate for electronic devices, 3-fold coordinated Hex BN has attracted much attention in recent years. However, this material is fabricated only in the form of small flakes. [3] There has been a limited amount fabricated in the

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Optical and structural properties of BGaN layers grown on different substrates

Cited by 24 publications

References 21 publications

BAlGaN alloys nearly lattice-matched to AlN for efficient UV LEDs

BAlGaN alloys nearly lattice-matched to AlN for efficient UV LEDs

Boron influence on bandgap and photoluminescence in BGaN grown on AlN

Effect of Film Thickness on Structural Stability for BAlN and BGaN Alloys: Bond‐Order Interatomic Potential Calculations

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