### 2.4.5 Summary to: 2.4: Other Semiconductors and Related Products

| Germanium (Ge) and SiC |  |
|  | Germanium was almost "useless" but is experiencing some comeback now (2007) in conjunction with Si technology. |
|  | SiC is very difficult to obtain as a good single crystal (many polytypes) but has some desirable properties for high speed or high power devices |
| II-Vl semiconductors are objects of heavy research but hardly used for products at present. |
|  | The only used material is CdTe for solar cells that are actually on the market. We might see, maybe, ZnO being used for LED's in the future. |  |
| "Chalcogenides", meaning compounds with "Chalcogens", i.e. S, Se, and Te as major elements, are often semiconductors |  |
|  | Oxygen, in the same IIa group, forms "oxides"! |  |
|  | The most prominent representative of chalcogenides (besides CdTe) is "CIS" (CuInSe2) or better "CIGS" (CuInxGa1-xSe2) used for solar cells and actually on the market. |  |
| Organic semiconductors. A relatively recent addition to the club, organic semiconductors seem to have a bright future at least in optoelectronics |  |
|  | OLED's are on the market, in particular as part of a flat panel display; the first OLED based TV screen has been announced for 2008. |  |
|  | The big problem of OLED's is their sensitivity to oxygen. |  |
Exercise 2.4-1
Some quick questions to 2.4

© H. Föll (Semiconductor Technology - Script)