Electrical Properties and Optical Absorption of SnSe Evaporated Thin Films

Resistivity, Hall effect, and optical absorption coefficient measurements are performed on SnSe evaporated thin films. The resistivity decreases with increasing temperature whereas the Hall mobility and carrier density increase with increasing temperature. An exponential 1/T law is observed for each of these variations. The results are explained in terms of a grain boundary potential barrier mechanism. The optical absorption coefficient is measured at 300 K over the photon energy range 0.8 to 1.3 eV. An analysis of absorption measurements indicates that the SnSe thin film absorption edge is due to allowed direct transitions across an energy gap of about 1.21 eV. Les proprietes de transport et les variations du coefficient d'absorption des couches minces de SnSe ont ete determinees. Quand la temperature croǐt, la resistivite diminue tandis que la mobilite et la concentration de porteurs augmentent. Les variations de ϱ, μ et p obeissent a une loi exponentielle en 1/T. Les resultats ont ete interpretes par le modele de barrieres de potentiel au niveau des joints de grains. Le coefficient d'absorption a ete determine a 300 K dans la region 0,8 a 1,3 eV. L'analyse des resultats obtenus indique que le SnSe en couche mince presente une transition directe avec une largeur de bande interdite de l'ordre de 1,21 eV.