Thermionic electron emission from nitrogen-doped homoepitaxial diamond

Kataoka, Mitsuhiro; Zhu, Chiyu; Koeck, Franz A.; Nemanich, R. J.

doi:10.1016/j.diamond.2009.09.002

Cited by 37 publications

(24 citation statements)

References 12 publications

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“…Several studies of H-terminated nitrogen-doped single-crystal diamond surfaces have shown thermionic emission with a work function of ≈2 eV. [261] The value is higher than anticipated, and has been attributed to the deep donor level for nitrogen (1.7 eV) and the presence of upward band bending. Studies of thermionic emission from polycrystalline n-and p-doped diamond have shown exceedingly low work functions of 1.4 and 0.9 eV, respectively.…”

Section: Vacuum Electronicsmentioning

confidence: 94%

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

Tsao

Chowdhury

Hollis

et al. 2017

Adv Elect Materials

980

463

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Section: Vacuum Electronicsmentioning

confidence: 94%

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

Tsao

Chowdhury

Hollis

et al. 2017

Adv Elect Materials

980

463

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“…Some of the investigations based on thermionic emission from nitrogen doped homoepitaxial diamond [18], nano [19] and ultrananocrystalline diamond [20] films have resulted in observed work functions as low as 1.3 eV. In other instance, thermionic emission energy distribution (TEED) results on undoped diamond films have been shown to exhibit work function value of 3.3 eV [21].…”

mentioning

confidence: 96%

Thermionic emission from phosphorus (P) doped diamond nanocrystals supported by conical carbon nanotubes and ultraviolet photoelectron spectroscopy study of P-doped diamond films

Sherehiy

Dumpala

Sunkara

et al. 2014

Diamond and Related Materials

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Materials with low work function values (< 2 eV) are highly in demand for low temperature thermionic electron emission, which is a key phenomenon for waste heat recovery applications.Here we present the work function reduction of phosphorus (P) doped (i) diamond nano crystals grown on conical carbon nanotubes (CCNTs) and (ii) diamond films grown on silicon substrates.Thermionic emission measurements from phosphorus doped diamond crystals on CCNTs resulted in work function value of 2.23 eV. The CCNTs provide the conducting backbone for the P-doped diamond nanocrystals and the reduced work-function is interpreted as due to the presence of midband-gap state and no evidence for negative electron affinity was seen. However, Ultraviolet photo-spectroscopy studies on phosphorus doped diamond films yielded a work function value of ~1.8 eV with a negative electron affinity (NEA) value of 1.2 eV. Detailed band diagrams are presented to support the observed values for both cases.

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“…For single crystal diamond, it has been established that hydrogen-terminated surfaces display a NEA, and n-type character is obtained through doping with nitrogen or phosphorus (Figure 2) (van der Weide et al, 1994;Diederich et al, 1998;Kataoka et al, 2010). Nitrogen-and phosphorus-doped diamond exhibit deep donor levels at ~1.7 and 0.6 eV, respectively.…”

Section: Diamond and Wide-bandgap Semiconductorsmentioning

confidence: 99%

Thermionic Energy Conversion in the Twenty-first Century: Advances and Opportunities for Space and Terrestrial Applications

Haase

George

et al. 2017

Front. Mech. Eng.

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Thermionic energy conversion (TEC) is the direct conversion of heat into electricity by the mechanism of thermionic emission, the spontaneous ejection of hot electrons from a surface. Although the physical mechanism has been known for over a century, it has yet to be consistently realized in a manner practical for large-scale deployment. This perspective article provides an assessment of the potential of TEC systems for space and terrestrial applications in the twenty-first century, overviewing recent advances in the field and identifying key research challenges. Recent developments as well as persisting research needs in materials, device design, fundamental understanding, and testing and validation are discussed.Keywords: thermal energy conversion, thermionic energy conversion, thermionic emission, heat engine, electron emission iNTRODUCTiON The direct conversion of heat to electricity without any intermediate steps or moving parts remains one of the most promising, yet challenging, methods of power production. The promise of high conversion efficiency, device simplicity, and robust operation continues to push research and technology development at the cutting edge. Furthermore, because of the wide variety of possible heat sources, ranging from combustion of fossil or other fuels, nuclear reactors, solar heat, or even waste heat from the human body, the applications for thermal-to-electric energy convertors are vast, spanning many orders of magnitude of possible temperature and power ranges.Thermionic energy conversion (TEC) for direct conversion of heat to electrical energy occurs when electrons thermally emit from a hot surface, traverse a gap, and are collected by another surface. This process, starting with thermionic emission, produces a current of electrons that can subsequently drive an electrical load to produce work. Particularly well suited for high-temperature applications, since it was first proposed by Schlichter (1915), thermionic emission has been pursued as a power generation method for over a century Gyftopoulos, 1973, 1979), yet has seldom been realized in either space or terrestrial applications. However, recent advances in material science and nanotechnology as well as our evolving understanding of the underlying physical processes afford new opportunities to develop practical thermionic convertors, reinvigorating the field. Thermionic energy conversion has a long and storied history, particularly in the space programs of the United States and the former Soviet Union. However, while the field was vibrant and much progress was made during the 1960s through 1980s, including space flight demonstrations, TEC has largely been supplanted by alternative energy conversion technologies, specifically thermoelectrics and photovoltaics, in both the public and research community consciences. Much of thermionic-based research tapered off after a 2001 report by the National Research Council titled Thermionics Quo Vadis? An Assessment of the DTRA's Advanced Thermionics Research and Development Program (Na...

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Thermionic electron emission from nitrogen-doped homoepitaxial diamond

Cited by 37 publications

References 12 publications

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

Thermionic emission from phosphorus (P) doped diamond nanocrystals supported by conical carbon nanotubes and ultraviolet photoelectron spectroscopy study of P-doped diamond films

Thermionic Energy Conversion in the Twenty-first Century: Advances and Opportunities for Space and Terrestrial Applications

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