Negative electron affinity of the GaN photocathode: a review on the basic theory, structure design, fabrication, and performance characterization.

Wang, Xiaohui; Wang, Mengbo; Liao, Yulong; Yang, Lifeng; Ban, Qipei; Zhang, Xiang; Wang, Zhenying; Zhang, Shibo

doi:10.1039/d1tc03244e

Cited by 24 publications

(10 citation statements)

References 99 publications

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“…Furthermore, a more detailed information about GaN-based photocathodes can be found in a recently published review. 142…”

Section: Semiconductor Photocathodesmentioning

confidence: 99%

“…As a rule, usually Mg-doping is used to create a p-type GaN semiconductor and an optimal hole concentration of 10 17 cm À3 is desired to achieve high QE. 142 Some publications refer to the Mg concentration instead of the hole concentration, whereby the hole concentration is estimated to be two orders of magnitude lower than the introduced Mg concentration. 143 5.4.1 Quantum efficiency.…”

Section: Gallium Nitridementioning

confidence: 99%

“…150,151 The optimal emission layer thickness was found between 90-200 nm. 142 p-GaN nanowire photocathodes show higher QE than planar p-GaN photocathodes. 152 Xia et al showed that the QE can be even further increased by using exponentially doped GaN nanowires.…”

Section: Gallium Nitridementioning

confidence: 99%

“…Furthermore, a more detailed information about GaN-based photocathodes can be found in a recently published review. 142 6 Other photocathode ideas A new idea is to use photocathodes with nano diamond layers, which can guarantee a higher QE than metal photocathodes. 166 The production with a pulsed spray technique is easier and has more advantages compared to CVD methods that need a hot substrate.…”

Section: Gallium Nitridementioning

confidence: 99%

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Review of photocathodes for electron beam sources in particle accelerators

2023

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“…Furthermore, a more detailed information about GaN-based photocathodes can be found in a recently published review. 142…”

Section: Semiconductor Photocathodesmentioning

confidence: 99%

Section: Gallium Nitridementioning

confidence: 99%

Section: Gallium Nitridementioning

confidence: 99%

Section: Gallium Nitridementioning

confidence: 99%

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Review of photocathodes for electron beam sources in particle accelerators

2023

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“…The susceptibility of the Cs layer to moisture and radiation negates the inherent advantages of III-nitride materials such as radiation-hardness and chemical stability. A thorough review of Cs/Cs-O activated GaN photocathodes, including device design, fabrication and performance has recently been published by Wang et al [41].…”

Section: Fig 2 Quantum Efficiency Of Ga-polar Photocathode Samplesmentioning

confidence: 99%

Overview and Progress Toward High-Efficiency, Air Stable, Cs-Free III-Nitride Photocathode Detectors

et al. 2022

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We review the recent progress to achieve air stable III-nitride photocathodes for applications as photon detectors. High conductivity p-type films are critically important to realize high quantum efficiency (QE) photocathodes with effective negative electron affinity (NEA) and downward surface band bending with narrow surface depletion width. Initial reports of III-nitride photocathodes utilize a Cs-surface activation to achieve effective NEA. To attain air stable, Cs-free photocathodes, novel energy band engineering has been shown using Si delta-doping and an n + -GaN cap on the surface of a Gapolar p-GaN layer. Improvement of QE has been achieved utilizing the N-polarity of III-nitrides due to advantageous depletion and polarization charges at the surface. High QE > 25% has been demonstrated by improvements in p-type conductivity with improved Mg-dopant incorporation in N-polar hillock structures and by control over unintentional impurity incorporation and distribution. Further, the importance of achieving high p-type conductivity films is further shown through reviewing recent simulations of GaN photocathodes with varied band bending and hole concentrations. Through comparison of experimental photoemission with Monte Carlo simulations, band structure parameters such as electron effective mass in the conduction band valleys have been elucidated.

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Laser Technology for Perovskite: Fabrication and Applications

Wan,

Liu,

Zhang

et al. 2024

Adv Materials Technologies

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Perovskite has attracted considerable attention in the electronic and optical fields in recent years, fulfilling the requirements of the ever‐growing demand in energy, environment, security, and big data storage. Laser direct writing technology is a flexible and mask‐free approach for fabricating, structuring, modifying, and patterning perovskites. Laser irradiation can directly induce perovskites from precursors due to the photothermal and photochemical effects of laser. Therefore, various laser‐induced perovskites, such as perovskite quantum dots, nanowires, nanocrystals, and films, are summarized. In particular, the laser‐induced perovskites in glass are intensively investigated for their high stability and flexibility in 3D printing. The second part of this review examines various applications of perovskites based on laser technology, such as solar cells, flat lenses, microlasers, photoluminescence, lithography, sensors, optical encryption, and data storage. Diverse laser treatments employed for modulating and patterning perovskite devices, such as laser annealing, laser ablation, and laser‐induced defects, are discussed. Prospective challenges and future trends in this research field are also concluded.

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Negative electron affinity of the GaN photocathode: a review on the basic theory, structure design, fabrication, and performance characterization.

Abstract: NEA GaN based on photocathode has important applicable prospects in vacuum electron source and ultraviolet detection due to its directly wide bandgap, high quantum efficiency, and robust characteristics. In recent...

Cited by 24 publications

References 99 publications

Review of photocathodes for electron beam sources in particle accelerators

Review of photocathodes for electron beam sources in particle accelerators

Overview and Progress Toward High-Efficiency, Air Stable, Cs-Free III-Nitride Photocathode Detectors

Laser Technology for Perovskite: Fabrication and Applications

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