Question 4 (i) Explain how you would use optical absorption measurements to differentiate between a direct and indirect gap semiconductor? (ii) Where would you expect to measure the optical absorption edge in germanium at 4 K? The indirect band gap is 0.74 eV at this temperature. Hint: the phonon energies for germanium at the L point are Longitudinal acoustic (LA): 0.027 eV Transverse acoustic (TA): 0.008 eV Longitudinal optic (LO): 0.030 eV Transverse optic (TO): 0.035 eV

Question 4 (i) Explain how you would use optical absorption measurements to differentiate between a direct and indirect gap semiconductor? (ii) Where would you expect to measure the optical absorption edge in germanium at 4 K? The indirect band gap is 0.74 eV at this temperature. Hint: the phonon energies for germanium at the L point are Longitudinal acoustic (LA): 0.027 eV Transverse acoustic (TA): 0.008 eV Longitudinal optic (LO): 0.030 eV Transverse optic (TO): 0.035 eV

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter1: Atomic Structure

Section: Chapter Questions

Problem 6RQ: How many valence electrons are generally contained in materials used for insulators?

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