Semiconductors Under Extreme Conditions

The importance of exploring physical properties and phase transitions of semiconductors under extreme conditions of high pressure P and/or high temperature T are illustrated using basic thermodynamic concepts. The specific role of XAS in the investigation of amorphous or liquid systems is addressed with emphasis on its unique sensitivity to the short range order. Current techniques for the performance of high-pressure and/or high temperature XAS measurements are briefly reviewed. Examples of XAS results on simple systems such as liquid and amorphous selenium and germanium are discussed.