The microstructure and electrical conductivity of mixed-valence TlIn4S5Cl quaternary compound micro- and nanowires

Quaternary mixed-valence compound TlIn4S5Cl micro- and nanowires are prepared by partial substitution of chalcogen with halogen starting from a stoichiometric mixture of TlCl, In and S. Their electrical conductivity and gas sensitivity properties are investigated by using standard four-terminal systems. The specific nanowire resistivity is about 107 Ω cm and corresponds to the value of a typical undoped semiconductor in air. This resistivity is, however, extremely sensitive to NO2 (sensitivity about 150) or NH3, with a rapid response of about 2 s and recovery times. This phenomenon is supposed to be particularly important for future nanodevice applications