Diamond dielectric constant

Electrical and Electronic. Diamond is an electrical insulator (-- lO H/cm) unless doped with boron when it becomes ap-ty e semiconductor with a resistivity in the range of 10 to 100 Q/cm. n-Ty e doping has often been claimed but is less certainly estabUshed. The dielectric constant of diamond is 5.58. 

The parameter is obtained by relating the static dielectric constant to Eg and taking in such crystals to be proportional to a - where a is the lattice constant. Phillips parameters for a few crystals are listed in Table 1.4. Phillips has shown that all crystals with a/ below the critical value of0.785 possess the tetrahedral diamond (or wurtzite) structure when f > 0.785, six-fold coordination (rocksalt structure) is favoured. Pauling s ionicity scale also makes such structural predictions, but Phillips scale is more universal. Accordingly, MgS (f = 0.786) shows a borderline behaviour. Cohesive energies of tetrahedrally coordinated semiconductors have been calculated making use... 

Fig. 15. Comparison of experimental (for the CLD-OMet chromophore in PMMA) and theoretical (equilibrium statistical mechanical calculations described in the text) data. Experimental data are denoted by solid diamonds. The solid line theoretical curve was computed without adjustable parameters. Quantitative agreement can be obtained by adjusting parameters (chromophore dipole moment, molecular polarizability, shape, and host dielectric constant) within reasonable limits. The theoretical curve can be broken down into two parts. The purely electronic part of the electrostatic interaction is shown by the dashed line. The steric effect of nuclear repulsive interactions is shown by the dotted line...

Fig. 41. Dependence of the most probable unperturbed chain dimension A on the dielectric constant e of the solvent for cellulose acetate (CA)-solvent systems7). Broken line the unperturbed chain dimension of a hypothetical cellulose with free internal rotation. Open marks Am values estimated from experimental data closed marks asymptotic Am values at the limit of e = 1. Circles CA(0.49) diamond CA(1.75), triangles CA(2.46) rectangle CA(2.92)...

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. 

Fig. 17.3 Polarization anisotropy ratio as a function of reduced optical radius ka, where e is the dielectric constant of the material. Solid (broken) lines are the theoretical curves for Si (SiC) NWs. Circles (diamonds) are the experimental values for Si (SiC) NW optical phonon (TO) lines (With permission from reference [12]. Copyright (2006) by the American Physical Society)...

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. 

In the parentheses, d, s and w stand for diamond, sphalerite, and wurtzite, respectively. For elemental crystals, e decreases continuously from oo to es. For compound semiconductors, is for energies above Eho and s for energies below Kto In wurtzite-type crystals, the first and second values of the dielectric constants are for E//c and E Lc, respectively... 

Face-centered cubic crystal lattice. Burns when heated with a hot enough flame (over 800, oxygen torch), df 3.513. rt 2 4173. Hardness — 10 (Mohs scale), Sp heat at 100°K 0.606 cal/g-atom/ K. Entropy at 298.I6 K 0,5684 cal/g-atom/ K. Band gap energy 6.7 ev. Dielectric constant 5.7. Electron mobility —1800 cm1/v-sec. Hole mobility 1200 cmz/v-sec. Can be pulverized in a steel mortar. Attacked by laboratory -type cleaning soln (potassi um dichromate + coned HiSO ), In the jewelry trade the unit of weight for diamonds is one carat — 200 mg. Ref Wall Street J. 164, no. 36, p 10 (Aug 19, 1964),... 

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