seminars

Thermionic energy conversion based on doped polycrystalline diamond films

Physical and Analytical Chemistry Seminar

Lecturer: Sergey Elfimchev

Date:
17-17 Mar 2019 @ 12:30

Location: Faculty Seminar Room

Abstract:

Thermionic energy convertor (TEC) transforms heat directly into electricity based on a thermionic effect and may have a lot of advantages relative to other engines. However, a TEC system requires electrodes with extremely low work functions, which is obviously difficult to attain.  Diamond is suggested to be a promising candidate for electron emission because of its low or even negative electron affinity (NEA) [1]. Recently, work function values of less than 1eV were reported for a phosphorus-doped polycrystalline diamond (Poly-Di) film [2-3]. In this work we proposed novel TEC based on nitrogen and phosphorus-doped Poly-Di films with very high theoretical conversion efficiencies.

Novel methods for phosphorus and nitrogen incorporation into diamond films were developed in this work. We investigated the aspects of nitrogen-doped diamond growth from ammonia, methane and hydrogen precursors by hot filament CVD (HFCVD) method. For phosphorus incorporation into diamond film the simple and safe method was developed based on red phosphorus controllable evaporation into HFCVD system. In this report we also present the consistent study of Moly/NCD/N-doped Di multilayer electrode construction, and also the impact of different deposition conditions on electron emission properties.

 

References:

  1. W.F. Paxton, A. Steigerwald, M. Howell, N. Tolk, W.P. Kang, J.L. Davidson, Theeffect of hydrogen desorption kinetics on thermionic emission frompolycrystalline chemical vapor deposited diamond, Appl. Phys. Lett. 101(2012) 243509.
  2. F.A.M. Koeck, R.J. Nemanich, A. Lazea, K. Haenen, Thermionic electron emission from low work-function phosphorus doped diamond films, Diam. Relat. Mater. 18 (2009) 789–791.
  3. S. Koizumi, Growth and characterization of phosphorus doped n-type diamond thin films, Phys. Status Solidi Appl. Res. 172 (1999) 71–78.