Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

While in edge dislocation, dislocation line is perpendicular to the Burger\'s ve

ID: 514253 • Letter: W

Question

While in edge dislocation, dislocation line is perpendicular to the Burger's vector, in screw dislocation, dislocation line is parallel to it. x. The flux of diffusing atoms increase as the temperature of the material decreases. xi. Many compound semiconductors have ZnS crystal structure, which is similar to diomond cubic, as the constituting elements have very similar electronic structures to C or Si forming bond hybridization; xii. Silica can be glassy or crystalline depending on the long-range ordering of the Si^2+ and O^2- ions; xiii. In steady state, diffusion does not depend on the concentration gradient; xiv. Doping with P, i.e., point defect formation, allows electron injection into Si, the major seminconductor enabling many current electronic devices; xv. The mixing of elements, the basis of all technological compounds (e.g., Stell used for construction, doped Si used for computer integrated circuits or solar cells, Al alloys for airplanes, medical implants such as Ti-alloys or zirconia, piezoelectric materials such as barium titanate), is enabled by mass transport in the solid state via diffusion of atomic species.

Explanation / Answer

ix) TURE

In an edge dislocation, the Burgers vector is perpendicular to the line direction. Edge dislocation line moves parallel to applied stress.

In screw dislocations, the Burgers vector is parallel to the line direction. In screw dislocation line moves perpendicular to applied stress

x) TURE

Flux of diffusing atoms increase as temperature of material decreases.

For non-ideal solutions Fick's first law can be written as

Ji = - (Dci /RT)(µi /x)

i denotes the ith species

c is the concentration (mol/m3)

R is the universal gas constant (J/K/mol)

T is the absolute temperature (K)

is the chemical potential (J/mol).

xi) TRUE

Diamond cubic is in the Fd3m space group. ZnS space group is F43m, but many of its structural properties are quite similar to the diamond structure. Zinc blende structures have higher packing factors than diamond depending on the relative sizes of their two component atoms.

xii) FALSE

Silica, as formed by the chemical reaction of silicon and oxygen can be either crystalline or amorphous. Depending upon the temperature, pressure and the rate of cooling, solid silica can take up different forms.Both form silica possesses SiO4 units.