Downloaded 53 times
Uploaded byChris Sonntag
Inorganic materials 1/2
1) The document discusses the properties of inorganic materials such as transition metal oxides and their crystal structures including octahedral and tetrahedral holes. It also covers band theory and how it relates to the electrical, optical, and magnetic properties of solids. 2) Band theory is used to explain the differences between conductors, semiconductors, and insulators. In conductors there is overlap between the filled valence band and empty conduction band allowing electrons to move freely. Semiconductors like silicon have a small band gap that can be overcome by thermal excitation. 3) Common semiconductor materials are elements in columns IV like silicon and germanium, and III-V compounds like gallium arsenide.
More Related Content
Similar to Inorganic materials 1/2
Inorganic materials 1/2
- 1. Inorganic Materials (1) Electrical,Optical and Magnetic Properties of solids Dr.Chris, UP April 2018
- 2.
- 3. Properties of Transition Metaloxides Dr. Christoph, UP April 2018
- 6.
- 8. Crystal Structures Octahedral holes = noof O2- Tetrahedral holes = ½ of octahedral
- 9. Spinel Types M2+M3+ 2 O4
- 10.
- 11.
- 15. Positions in acrystal = in the center M = middle of a edge R = at the edge
- 16.
- 17.
- 20. Metals - Conductors Example: Combiningthe 2s orbitals of several Li- atoms => For each 2s AO we get one MO https://chem.libretexts.org/Textbook_Maps/General_Chemistry_Textbook_Maps/Map%3A _Chem1_(Lower)/09._Chemical_Bonding_and_Molecular_Structure/9.10%3A_Bonding_in _Metals
- 21. Finally we endup with 2 “bands” Electrons can move freely in the empty orbitals (anti-bonding MO’s)
- 22. In conductors, thereis overlap between the filled and empty orbitals => Electrons from the valence band can easily move into the conduction band Conduction band Valence band
- 23. The melting points( ~ the strength which that atoms are held together) first raise from 1st row onwards, since more and more electrons are in valence bands. But there is a maximum in the middle of the Periodic Table: with increasing nuclear charge, the harder it is to remove electrons into the conduction band. https://chem.libretexts.org/Textbook_Maps/Ge neral_Chemistry_Textbook_Maps/Map%3A_Ch emPRIME_(Moore_et_al.)/22Metals/22.01%3A _Metallic_Bonding Melting points of metals
- 24.
- 25. Example: Silicon as“IV semiconductor”
- 26. Example: Si crystal Thecloser the atoms come together, the higher the band gap will be ! LUMO HOMO https://www.youtube.com/watch?v=k_tFJin_YoQ
- 28.
- 30.
- 32.
- 33.
- 34. The probability tofind and electron in the conductor band can be calculated as: https://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Chemical_Bonding/F undamentals_of_Chemical_Bonding/Band_Structure
- 35.
- 36. Typical semiconductors Elements: • With4 valence electrons: Si, Ge • With 3 and 5 VE: GaAs, GaP, GaSb
- 37. III-V semiconductors The smallerthe lattice constant, the higher the band gap energy
- 38.
- 40. https://www.azonano.com/article.aspx?ArticleID=4226 Measure the bandgap energy by UV/VIS
- 42. Fermi Level EF(metals) EF = 50% probability level to find an electron https://www.youtube.com/watch?v=zWOSAzbxTrE
- 43. For semiconductors, EFis in the middle of the band gap The higher T, the more electrons will come up to the conductive band – at 0 K, all electrons are in the valence band T up Charge carriers are electrons and holes