ESR STUDY OF ALKALI-DOPED POLYACENIC SEMICONDUCTOR (PAS) MATERIALS PREPARED BY THERMAL-DECOMPOSITION OF AZIDES

The alkali-doped polyacenic semiconductor (PAS) materials have been pr epared by thermal decomposition of alkali azides (AN(3), where A=Li, N a, K and Rb) in vacuo, and their electronic properties have been studi ed based on the electron spin resonance (ESR) spectral measurements as functions of atomic number (Z) of the dopant metal and of temperature (T) in the range 2-300 K. From the ESR spectrum, it was confirmed tha t the PAS material was successfully doped by a certain amount of alkal i metal. The value of ESR linewidth was found to increase with Z and t o linearly decrease with decreasing T. This behavior strongly suggests that conduction electrons generated by the doping have some probabili ty to locate on the dopant metal atom and that such a location is prob ably suppressed at low temperatures in a rather uniform manner irrespe ctive of metal species. (C) 1997 Elsevier Science Ltd.