Growth and device processing of hexagonal boron nitride epilayers for thermal neutron and deep ultraviolet detectors

Doan, T. C.; Li, J.; Lin, J. Y.; Jiang, H. X.

doi:10.1063/1.4959595

Cited by 29 publications

(43 citation statements)

References 28 publications

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“…Table II summarizes the performance of semiconductor based solar-blind PDs. 88,[96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111][112][113] The table is ordered by the use of different groups of materials. As indicated in the table, III-nitride based PDs are among the first and ideal choices for high efficiency and high-speed devices.…”

Section: Detectorsmentioning

confidence: 99%

Light based underwater wireless communications

Oubei

Shen

Kammoun

et al. 2018

Jpn. J. Appl. Phys.

121

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Underwater wireless optical communication (UWOC) is a wireless communication technology that uses visible light to transmit data in underwater environment. Compared to radio-frequency (RF) and acoustic underwater techniques, UWOC has many advantages including large information bandwidth, unlicensed spectrum and low power requirements. This review paper provides an overview of the latest UWOC research. Additionally, we present a detailed description of transmitter and receiver technologies which are key components of UWOC systems. Moreover, studies investigating underwater optical channel models for both simple attenuation and the impact of turbulence including air bubbles and inhomogeneous salinity and temperature are also described. Future research challenges are identified and outlined.

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Section: Detectorsmentioning

confidence: 99%

Light based underwater wireless communications

Oubei

Shen

Kammoun

et al. 2018

Jpn. J. Appl. Phys.

121

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“…7(a). [9][10][11] The system design was adopted from the thesis work of Clinton 17,30 and based on a depleted sealed source, model 100 californium-252 source ( 252 Cf) which contained 4.2 lg of active 252 Cf from Frontier Technology, emitting fission neutrons, moderated by a high density polyethylene (HDPE) block. The experimental geometry and HDPE size and thickness are identical to those described in the thesis.…”

Section: Vlsmentioning

confidence: 99%

“…It is important to point out that the BN interaction with gamma photons is exceptionally low due to the fact that BN is composed of low atomic number elements. 9,11 Our previous measurement results have demonstrated that h-BN detectors have a negligible response to c-photons produced by 137 Cs decay with an energy at 0.662 MeV and possess a neutron-gamma rejection ratio larger than 10 6 . 9,11 Corroborating with the leakage current and ls-product results, the measured neutron detection efficiency results also indicate that one of the prominent effects on the detector performance is the choice of ohmic contact material and that the Ni/Au bilayer is the preferred choice over the Ti/Al bilayer.…”

Section: Vlsmentioning

confidence: 99%

“…Hexagonal boron nitride (h-BN), a wide bandgap ($6.5 eV) semiconductor, known for its deep ultraviolet photonic applications, [1][2][3][4][5][6][7] has emerged as an outstanding neutron detector material [8][9][10][11][12][13][14] due to the fact that the B-10 ( 10 B) isotope has a large capture cross section for thermal neutrons (3840 b or 3.84 Â 10 À21 cm 2 ). Special nuclear materials (SNMs) tend to emit neutrons through fission reactions.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, solid-state neutron detectors that have the performance of 3 2 He detectors without their drawbacks are highly soughtafter technologies. [8][9][10][11][12][13][14][16][17][18][19][20][21][22] As a semiconductor, the density of atoms that can interact with thermal neutrons in 100% 10 B-enriched h-BN [N( 10 B) ¼ 5.5 Â 10 22 /cm 3 ] is about 550 times higher than that in He-3 gas pressurized at 4 atm, providing an absorption length (k) of thermal neutrons in h- 10 BN of only 47 lm, where k ¼ (3.84 Â 10 À21 cm 2 Â 5.5 Â 10 22 /cm 3 ) À1 ¼ 0.0047 cm. 13,14 This length scale is negligibly small compared to the diameters of typical 3 2 He detectors.…”

Section: Introductionmentioning

confidence: 99%

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Hexagonal boron nitride neutron detectors with high detection efficiencies

Maity

Grenadier

et al. 2018

Journal of Applied Physics

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Neutron detectors fabricated from 10 B enriched hexagonal boron nitride (h-10 BN or h-BN) epilayers have demonstrated the highest thermal neutron detection efficiency among solid-state neutron detectors to date at about 53%. In this work, photoconductive-like vertical detectors with a detection area of 1 Â 1 mm 2 were fabricated from 50 lm thick free-standing h-BN epilayers using Ni/Au and Ti/Al bilayers as ohmic contacts. Leakage currents, mobility-lifetime (ls) products under UV photoexcitation, and neutron detection efficiencies have been measured for a total of 16 different device configurations. The results have unambiguously identified that detectors incorporating the Ni/Au bilayer on both surfaces as ohmic contacts and using the negatively biased top surface for neutron irradiation are the most desired device configurations. It was noted that high growth temperatures of h-10 BN epilayers on sapphire substrates tend to yield a higher concentration of oxygen impurities near the bottom surface, leading to a better device performance by the chosen top surface for irradiation than by the bottom. Preferential scattering of oxygen donors tends to reduce the mobility of holes more than that of electrons, making the biasing scheme with the ability of rapidly extracting holes at the irradiated surface while leaving the electrons to travel a large average distance inside the detector at a preferred choice. When measured against a calibrated 6 LiF filled micro-structured semiconductor neutron detector, it was shown that the optimized configuration has pushed the detection efficiency of h-BN neutron detectors to 58%. These detailed studies also provided a better understanding of growth-mediated impurities in h-BN epilayers and their effects on the charge collection and neutron detection efficiencies.

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Recent Progress in Solar‐Blind Deep‐Ultraviolet Photodetectors Based on Inorganic Ultrawide Bandgap Semiconductors

Xie

Tong

et al. 2019

Adv Funct Materials

410

261

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Due to its significant applications in many relevant fields, light detection in the solar-blind deep-ultraviolet (DUV) wavelength region is a subject of great interest for both scientific and industrial communities. The rapid advances in preparing high-quality ultrawide-bandgap (UWBG) semiconductors have enabled the realization of various high-performance DUV photodetectors (DUVPDs) with different geometries, which provide an avenue for circumventing numerous disadvantages in traditional DUV detectors. This article presents a comprehensive review of the applications of inorganic UWBG semiconductors for solar-blind DUV light detection in the past several decades. Different kinds of DUVPDs, which are based on varied UWBG semiconductors including Ga 2 O 3 , Mg x Zn 1−x O, III-nitride compounds (Al x Ga 1−x N/AlN and BN), diamond, etc., and operate on different working principles, are introduced and discussed systematically. Some emerging techniques to optimize device performance are addressed as well. Finally, the existing techniques are summarized and future challenges are proposed in order to shed light on development in this critical research field.with energy much higher than the semiconductor bandgap. Moreover, due to light absorption by the surface passivation layers, typically Si oxide, quantum efficiency in the DUV range is greatly reduced. The passivation layers are also easily degraded by UV illumination. Finally, for highly sensitive UV photodetection, the detectors need to be cooled to reduce dark current; the cooled detectors, however, behave like cold traps for contaminants which degrade the detectivity.In the past two decades, the emergence of UV photodetectors based on wide-bandgap (WBG) semiconductors has opened up an avenue to circumvent the above-mentioned dilemma. The WBG semiconductors such as SiC, GaN, and some group II-V compounds, typically have bandgaps exceeding ≈3.10 eV, enabling room-temperature detectors to possess fast response speed, and offering intrinsic visible-blindness (response cutoff wavelength: ≈400 nm). [14][15][16] Moreover, these semiconductors generally possess significantly higher thermal conductivity than Si, which renders them suitable for operation in harsh environments (e.g., high temperature and high power). The electron velocity of these materials at large electric fields is generally higher than that of common semiconductors, although WBG semiconductors exhibit relatively lower electron and hole mobilities. Compared with the abovementioned conventional WBG semiconductors, ultrawide-bandgap (UWBG) semiconductors, as the next generation of semiconductor materials with bandgaps significantly wider than the 3.4 eV of GaN, are particularly suitable for solar-blind DUV light detection. [17][18][19][20]

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Growth and device processing of hexagonal boron nitride epilayers for thermal neutron and deep ultraviolet detectors

Cited by 29 publications

References 28 publications

Light based underwater wireless communications

Light based underwater wireless communications

Hexagonal boron nitride neutron detectors with high detection efficiencies

Recent Progress in Solar‐Blind Deep‐Ultraviolet Photodetectors Based on Inorganic Ultrawide Bandgap Semiconductors

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