Influence of grain boundaries and surface scattering on charge transport in PbTe, SnTe, and CdTe thin films

The thickness dependence of the electrical conductivity and charge-carrier mobility of freshly grown PbTe, SnTe, and CdTe thin films, deposited under identical conditions on flexible polyamide (PM-1) substrates, was studied at 300 K. Surface and grain-boundary scattering were analyzed over a wide thickness range. The effective mean free path, estimated from σ(1/d), is similar for PbTe and SnTe but smaller for CdTe, reflecting its electronic structure and microstructure. SnTe shows the highest conductivity owing to its high, degenerate (Sn-vacancy-induced) carrier concentration. Surface scattering dominates in thin films, while grain-boundary scattering grows with thickness.