Photoconductivity in the ternary layered semiconductors

Spectral dependences of the photoconductivity, near-band-edge absorption were studied at room and low temperatures for a number of TlInS2 and TlInSl(2) type layered ternary chalcogenides. Some peculiarities in the temperature dependences of the spectral properties are assigned as due to a low temperature phase transition to an incommensurate and ferroelectric state. Temperature coefficients of the band gap for TlInSe2 are determined. Spectral properties of TlInS2 doped with Nd and Yb are also presented and discussed it is shown that the long-wave length absorption edge of TlInS2 crystal obeys the Urbach's rule. High photosensitivitiy in the visible and near IR range of spectra makes these materials attractive for optoelectronics application.