1. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV 5.10 Ohmic contacts and thermoelectric coolers Fig 5.43 Ohmic contacts Metal, n-type semiconductor : Metal, p-type semiconductor :

2. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV Fig 5.44 Peltier effect

3. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV Fig 5.45 When a dc current is passed through a semiconductor to which metal contacts have been made, one junction absorbs heat and cools (the cold junction) and the other releases heat and warms (the hot junction). +++ - - - +++ - - -

4. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV Fig 5.46 Cross section of a typical thermoelectric cooler. Temp

5. SEMICONDUCTOR PHOTONICS LAB., HANYANG UNIV Fig 5.47 Typical structure of a commercial thermoelectric cooler.