Atomic, Molecular & Optical Physics

2012 PH682: Optical Properties of Semiconductors

A graduate course taught by the Department of Physics at Oregon State University. In 2012 the course is being taught by Prof. Ethan Minot during Week 6 - Week 10 of Winter term. The module is offered biyearly.

Calendar

DayTopicReadingSummaryAssignments
1M 2/13Below bandgap effectsA&M Ch27Cyclotron resonance (A&M p570). CNT anisotropic THz absorption. Plasma reflectivity edge at tens of THz. Absorption via lattice vibrations at tens of THz.HW #1
2W 2/15Below bandgap effects Optical properties in the transparency window: Frequency dependent dielectric constant, birefringence, non-linear optical materials
3F 2/17AbsorptionPankove Ch3 Direct bandgap semiconductor: density of directly associated states, absorption coefficient (inverse of penetration depth)hw1soln.pdf
DayTopicReadingSummaryAssignments
4M 2/20Absorption Exciting electrons across an indirect bandgap. Absorption coefficient for indirect transitions. Intro to excitons. Exciton RydbergHW #2
5W 2/22Excitons Experiments probing free excitons: Excitons generated by resonant absorption, excitons generated by ħω > E_g. Exciton Rydberg in 2-dimensional system.
6F 2/24Excitons, Light emission processes fox_5.3.2.pdfday6_2012.pdf day6_2012_rewritten.pdf: Tightly bound excitons. Radiative recombination and photoluminescence spectra. Excess carrier radiative recombination lifetime. hw2soln_2012.pdf
DayTopicReadingSummaryAssignments
7M 2/27Light emission processes Exciton spontaneous emission lifetime in a bulk crystal HW #3
8W 2/29Light emission processesS&T p515Quasi-Fermi Level. Measurements of exciton lifetimes. Purcell factor tunes spontaneous emission lifetime.
9F 3/2Laser DiodesCh 17 S&L, §5.43 FoxWaveguiding and restricted recombination region, quantum efficiency, quality factor of laser cavities hw3solns2012.pdf
DayTopicReadingSummaryAssignments
10M 3/5Laser DiodesS&T p732Laser diode: population inversion, incremental gain coefficient, gain guiding. Quantum Cascade Laser, worksheet to guide discussion of the quantum engineeringHW #4
11W 3/7PhotovoltaicsA&M Ch 29day11_2012.pdf: Best research efficiency, motivate derivation of Schockley-Queisser limit (intro to SQ limit). Deriving the ideal diode equation: generation currents and recombination currents, calculate reverse bias saturation current for a real example.
12F 3/9Photovoltaics day12_2012.pdf: Ideal diode under illumination: Short circuit current and open circuit voltage, calculating V_OC based on ideal diode curve, choosing material thickness, choosing load resistance, fill factor, reason for concentrating the sunlight.hw4solns_2012.pdf, hw4_qcl_question.pdf
DayTopicReadingSummaryAssignments
13M 3/12PhotovoltaicsDr. Cohen's 2010 Presentationday13_2012.pdf: Calculating maximum possible V_OC using Quasi-Fermi level concept, the solar spectrum and the room temperature blackbody background (the argument used by Schockley-Quisser), overview of the rest of S-Q argument Schockley-Queisser's 1961 article, final result of the S-Q argumentHW #5
14W 3/14Photovoltaics Discussion of ways to beat the S-Q limit.
15F 3/16Photovoltaics Guest Lecture: Dr. Robert Kykyneshi (thin-film photovoltaics) hw_5_2012.pdf

final

Syllabus

Below bandgap effects

  • Spectra of dielectric function and of complex index of refraction
  • Kramers-Kronig relations
  • Microscopic description of polarizability
  • Birefringence, Kerr rotation, Faraday effect, Voigt effect
  • The electron gas plasma resonance
  • Ensemble of uncoupled oscillators – classical and quantum

Interband excitations and emissions

  • Band-to-band transitions
  • Absorption cross-section
  • Exciton models (Wannier and Frenkel)
  • Exciton & defect state spectroscopy (including excited states & triplet/singlet)
  • Excitons in low-dimensional systems
  • Electron-hole plasma
  • Semiconductor Bloch equations (intro)

Phonons

  • Raman scattering
  • Phonon polaritons
  • Brillouin scattering

Semiconductor lasers

  • pn junctions
  • non-radiative transitions
  • tunable alloys
  • Purcell effect
  • cavity QED
  • quantum cascade laser

Photovoltaics

  • Optimal bandgap and Shockley–Queisser limit
  • Thin film solar cells