染料敏化太阳能PPT

Donor Level
Acceptor Level
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Carrier Concentration
•
• • •
電子濃度為態位密度(density of state) N(E)與費米分布函數(Fermi distribution) F(E) 之摺積(convolution)。
– – n = Nc exp [exp[-(Ec-EF)/kT] p = Nv exp [exp[-(EF-Ev)/kT]
Direct Bandgap
Indirect Bandgap
26
Effective Mass
• 等效質量是量子力學與古典力學之重要 橋樑 – 電子與電洞可以被視為古典物理中 之帶電粒子。 mn* (d2E/dp2)-1
– 等效質量等於能量-動量曲線中曲率的倒 數。 – 曲率越小，等效質量越大。 – 拋物線的開口越大，等效質量越大。
Acceptor(受體)
– Column II (Be, Zn, Cd, etc.) impurity substitute for column III (Ga)
Amphoteric impurity (雙性雜質)
– Column IV (Si) – substituting Ga for donor (low T) – substituting As for acceptor (high T)
21
Energy-Band Diagram
Metal
Semiconductor
Insulator
22
Simplified Energy-Band Diagram
23
Energy-Momentum Band Diagram
24
Band Structures for Si and GaAs
Si
GaAs
課程講義
半導體概論
南台科技大學光電系 吳坤憲
1
Introduction to Semiconductor Technologies
I. 半導體材料 (Materials) II. 半導體基本物理 (Physics) III. 半導體元件 (Devices) IV. 半導體製程 (Fabrication) V. 半導體 量測 (Characterization)
•
• • •
電洞的等效質量大於電子等效質量
– mp* > mn*
For Si: mn* = 0.26 m0, mp* = 0.69 m0 For GaAs: mn* = 0.063 m0, mp* = 0.57 m0
27
Fermi Level
• 費米能階(EF)為被電子佔有機 率為1/2的能量。 • 費米分布函數對稱於費米能階。
溫度 (Temperature)
– Thermal sensors
照光 (Illumination)
– optoelectronic devices : Photodetector, Solar Cell….ect..
摻雜 (Doping)
– 大幅增加導電度 – 形成P 型及N型半導體 – 形成P/N接面:多數半導體元件之基本結構
P-type Semiconductor (P型半導體)
– 多數載子(majority carrier)為電洞的半導體 – 矽晶體中摻雜III族原子則形成P型半導體
34
Impurities for III-V Compound Semiconductors
Donor (施體)
– Coluubstitute for column V (As)
14
Crystallization of materials
15
Crystal and Lattice
Crystal (結晶體)
– The semiconductor materials are basically assumed as single crystals to simplify the analysis.
– Si: ~ 105 – doped-Si: 105 ~ 10-5
•
Insulator
– Quartz: ~ 10-18 – Plastics: ~10-13 – GaAs: ~ 10-6
Resitivity (-cm) Conductivity (-cm)-1
7
Portion of the Periodic Table related to semiconductors
• 入門
– 導電性界於導体與絕緣體之間的材料
• 中階
– 電阻係數約為10-4 ~108 -cm的材料
• 進階
– 能隙約在 4eV以下之的材料
6
Solid-State Materials
•
Conductor
– Mn: ~ 105 – Cu: ~ 8 × 106 – Fe: ~ 107
•
Semiconductor
25
Direct and Indirect Bandgap Semiconductors
• •
Direct transition: band to band photon emission Indirect transition: via defect or impurity-related states phonon emission
2
Chapter I Semiconductor Materials
半導體材料
3
Semiconductor Materials
半導體材料
Solid-State Materials Semiconductor Materials Basic Crystal Structure Energy-band Diagram Intrinsic and Extrinsic
• • • • F(E) exp[-(E-EF)/kT] for (E-EF) > 3kT F(E) 1- exp[-(E-EF)/kT] for (E-EF) > 3kT
• 在室溫下，能量高於(低於) 3KT之能階可視為空態(滿態)
28
Extrinsic (Doped) Semiconductor
16
The Diamond Structure
(a) Diamond lattice.
(b) Zincblende lattice.
17
Crystal Plane and Direction
A (623)-crystal plane
Miller indices of some important planes in a cubic crystal
13
重要的半導體分類
• Element semiconductor • Compound semiconductor • Intrinsic semiconductor • Extrinsic semiconductor • Direct semiconductor • Indirect semiconductor • Degenerate semiconductor • Non-degenerate semiconductor • Compensated semiconductor • Non-compensated semiconductor

Lattice (晶格) – The periodic arrengment of atoms in a crystal Lattice Constant (晶格常數) – The dimension a is called the lattice constant
Three cubic-crystal unit cells. (a) Simple cubic. (b) Body-centered cubic (c) Face-centered cubic.
Si
Si
GaAs GaP 化合物 InP ZnSe ZnS
10
Various Semiconductor Materials
11
其他常用的半導體材料之相關名詞
• • • • Bulk (本體) Substrate (基板) Film (薄膜) Epitaxial layer (磊晶層)
12
改變半導體導電性的主要方法
Intrinsic Semiconductor (本質半導體)
– 導電電子數量與電洞數量大約相同的半導體 – 通常指未經摻雜的半導體(Undoped Semiconductor)
N-type Semiconductor (N型半導體)
– 多數載子(majority carrier)為電子的半導體 – 矽晶體中摻雜V 族原子則形成N型半導體
35
Carrier Concentration vs. Temperature
8
Element and Compound Semiconductors
Element semiconductors
Si, Ge, C (diamond).. , etc..
Compound Semiconductors
– III-V compound semiconductors
• Binary: GaAs, InP, GaP, GaN, AlAs, InAs… • Ternary: Al1-xGaxAs, GaAsxP1-x , InxGa1-xAs • Quaternary: InxGa1-xAsyP1-y
18
Covalence Bonds
A tetrahedron bond (a) 3-D. (b) 2-D
19
Conduction Electron and Hole