Electrothermal investigation of the switching phenomena in p-type TlInSe2 single crystals

Large TlInSe2 single crystals are grown by the Bridgman-Stockbarger method, starting from stoichiometric melts. Current–voltage (I–V) characterstics of symmetric In/p-TlInSe2/In structures exhibit two distinct regions: an ohmic region at low current densities and a non-linear region (S-shaped) having negative differential resistance (NDR) at moderate and higher current densities. An electrothermal model is used for the explanation of this non-linear behaviour. The non-linear behaviour of the I–V curves is studied at different ambient temperatures in the 100 to 340 K region. The sample temperature and the threshold voltage of the NDR region are examined as a function of current density and ambient temperature, respectively. The electrothermal model is quite satisfactory for the explanation of this process.