Carbon(diamond) and silicon have the same covalent crystal structure, yet diamond is transparent while silicon is opaque to visible light. Argue that this should be the case based only on the difference in band gaps roughly 5 eV for diamond in eV is silicon.

Short Answer

Expert verified

The value shows that the visible light is absorbed by the silicon but not by diamond.

Step by step solution

01

Determine the formulas

Consider the formula for the energy of the electron as:

E=hcλ

Here,λ is the wavelength, h is the plank’s constant, and c is the speed of light.

02

Determine the distance travelled and number of copper ions:

Consider the case of lower range 400 nm as:

E1=1240 eVnm400 nm=3.11 eV

Solve for the upper value of 750 nm as:

E2=1240 eVnm750 nm=1.66 eV

The value shows that the visible light is absorbed by the silicon but not by diamond.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Question: - For a small temperature change. a material's resistivity (reciprocal of conductivity) will change linearly according to

p(dT)=ρ0+dρ=ρ0(1+αdT)

The fractional change in resistivity, αalso known as the temperature coefficient, is thus

α=1ρ0dρdT

Estimate forα silicon at room temperature. Assume a band gap of 1.1 e v .

The bonding of silicon in molecules and solids is qualitatively the same as that of carbon. Silicon atomic states become molecular states analogous to those in Figure 10.14. and in a solid, these effectively form the valence and conduction bands. Which of silicon's atomic states are the relevant ones, and which molecular state corresponds to which band?

Question:In Chapter 4. we learned that the uncertainty principle is a powerful tool. Here we use it to estimate the size of a Cooper pair from its binding energy. Due to their phonon-borne attraction, each electron in a pair (if not the pair's center of mass) has changing momentum and kinetic energy. Simple differentiation will relate uncertainty in kinetic energy to uncertainty in momentum, and a rough numerical measure of the uncertainty in the kinetic energy is the Cooper-pair binding energy. Obtain a rough estimate of the physical extent of the electron's (unknown!) wave function. In addition to the binding energy, you will need to know the Fermi energy. (As noted in Section 10.9, each electron in the pair has an energy of about EF.) Use 10-3 eV and 9.4 eV, respectively, values appropriate for indium.

The bond length of theN2 molecule is0.11nm , and its effective spring constant is 2.3×103N/mat room temperature.

(a) What would be the ratio of molecules with rotational quantum number=1 to those with=0 (at the same vibrational level), and

(b) What would be the ratio of molecules with vibrational quantum numbern=1 to those with n=0(with the same rotational energy)?

Question: The interatomic potential energy in a diatomic molecule (Figure 10.16) has many features: a minimum energy, an equilibrium separation a curvature and so on. (a) Upon what features do rotational energy levels depend? (b) Upon what features do the vibration levels depend?

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free