Diamond dielectric properties

Q.F. Huang, S.F. Yoon, Rush, Q. Zhang and J. Ahn, Dielectric Properties of Molybdenum-containing Diamond-like Carbon Films Deposited Using Electron Cyclotron Resonance Chemical Vapor Deposition, Thin Solid Films, 409, 211-219 (2002). 

Measurements of dielectric loss in high quality CVD diamond at millimetre wave microwave frequencies, reported in 1993 [2], furnished for the first time clear evidence that the loss tangent of CVD diamond could be comparable or lower than conventional dielectrics such as sapphire or boron nitride. This initial data and subsequent first dedicated dielectric property studies [61] intensified the considerable amount of interest that had already existed in the nuclear fusion community for CVD diamond as a high power window material [62] especially for the development... 

Preliminary measurements of the temperature dependence of the dielectric properties of polycrystalline CVD diamond are available. Figures 29 and 30 show the temperature dependence of tan 5 and e r measured at 145 GHz for a CVD diamond sample compared to sapphire [75]. In this temperature range (100-370 K), the dielec-... 

Measurements of the effect of radiation on the dielectric properties of CVD diamond have been reported using neutron irradiation experiments with fast neutron fluences up to at least lO nm (energy >0.1 MeV) [65]. Differences before and after irradiation were found to be more pronounced at lower frequencies. At 145 GHz specimens that started with values of tan 5 of 2 x 10 maintained these levels (or even showed a decrease in loss). Further experiments to extend radiation fluencies to 10 nm are in progress [68]. 

GavrilMn SM, Poyarkov KB, Matseevich BV, Batsanov SS (2009) Dielectric properties of diamond powder. Inorg Mater 45 980-981... 

In Section 2 we showed that the properties of amorphous carbon vary over a wide range. Graphite-like thin films are similar to thoroughly studied carbonaceous materials (glassy carbon and alike) in their electrode behavior. Redox reactions proceed in a quasi-reversible mode on these films [75], On the contrary, no oxidation or reduction current peaks were observed on diamondlike carbon electrodes in Ce3+/ 41, Fe(CN)63 4. and quinone/hydroquinone redox systems the measured current did not exceed the background current (see below, Section 6.5). We conventionally took the rather wide-gap DLC as a model material of the intercrystallite boundaries in the polycrystalline diamond. Note that the intercrystallite boundaries cannot consist of the conducting graphite-like carbon because undoped polycrystalline diamond films possess excellent dielectric characteristics. 

Diamond has a number of properties, such as wide band gap, high breakdown electric field, and low dielectric constant, which make it an ideal candidate for semiconductor applications. Why has diamond not been used more often in semiconductor applications ... 

In the crystal lattice of diamond, each atom of carbon is surrounded tetrahedrally by four other atoms to which the central atom is bound by four (7 bonds. Each crystal is thus a large single molecule in which every atom is joined to four others by homopolar bonds. The bond between the carbon atoms is almost identical in properties with that of the single C—G bond in hydrocarbons, thus the interatomic distance in diamond is i 54 A and the value of the dielectric constant, 5 3, leads to a value for the polarizability of the bond of i cc, which is only slightly less than the value for the G—G bond in hydrocarbons. 

Properties Dark-colored crystals (the octahedral form in which the atoms have the diamond arrangement). The amorphous form is a dark-brown powder (see silicon, amorphous). D 2.33, mp 1410C, bp 2355C, Mohs hardness 7, dielectric constant 12, coordination number 6. Soluble in a mixture of nitric and hydrofluoric acids and in alkalies insoluble in water, nitric acid, and hydrochloric acid. Combines with oxygen to form tetrahedral molecules in which one silicon atom is surrounded by four oxygen atoms. In this respect it is similar to carbon. It is also capable of forming -Si=Si- double bonds in orga-nosilicon compounds. 

We study the dielectric and energy loss properties of diamond via first-principles calculation of the (0,0)-element ( head element) of the frequency and wave-vector-dependent dielectric matrix eg.g CQ, The calculation uses all-electron Kohn-Sham states in the integral of the irreducihle polarizahility in the random phase approximation. We approximate the head element of the inverse matrix hy the inverse of the calculated head element, and integrate over frequencies and momenta to obtain the electronic energy loss of protons at low velocities. Numerical evaluation for diamond targets predicts that the band gap causes a strong nonlinear reduction of the electronic stopping power at ion velocities below 0.2 a.u. 

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