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Nanoub Tutorial: 1

Chemistry

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Nanoub Tutorial: 1. Go to www.nanohub.org 2. Hit the menu tab at the top right of the screen.

3. On the left side of the page, hit "Sign Up".

4. Go through signing up and their verification process (usually through email).

5. Make sure to sign back in.

6. On the top of the page, click the Resources tab.

7. Now click on "Tools"

8. On the next page, you'll see "Tag", "Resources", and then "Info" each horizontally adjacent. a. Under "Tag" click "[All]" b. Under "Resources", click "ABACUS..." c. Under "Info", hit "Launch Tool"

9. Here, you will see this screen, which we will go to before all labs

10. Make sure to click on "Crystal Viewer Lab - NEW E+RELEASE"                                                                                        Now answer the below questions:                                                                                                                                  Using the Nanohub Crystal Viewer, visualize crystal structures of GaAs and NaCl.Determine the atomic densities and packing efficiencies for these materials. Discuss similarities and distinctions of these two structures and their genesis.Visualize the major atomic planes {100}, {110}, and {111}. Determine their densities in terms of atoms/(unit cell) and calculate their atomic density in (at/cm2 ).

- Explore the effect of alloying of GaAs with InAs on the crystal structure.

(i) Using the Vegard's law, calculate the effect of InAs fraction in Ga1-xInxAs (also can be presented as (GaAs)1-x(InAs)x) on the atomic density of the alloy material and plot, using computer software, lattice parameter of the alloy vs. InAs fraction x.

Calculate atomic densities of the major planes {100}, {110}, and {111} in the Ga1-xInxAs alloy and plot them vs. InAs fraction x. - Using Vegard's law, balance as close as s possible the alloy lattice parameter of quaternary alloy Ga1 - 0.2 - yIn0.2AlyAs (also can be presented as (GaAs)1 - 0.2 - y(InAs)0.2(AlAs)y) to the value of the lattice parameter of GaAs which is used as a substrate material for production of infra-red LED by adding appropriate portion of AlAs to GaInAs containing 20% In.                                                                                                                                                                    Discuss your finds and make conclusions