Growth of bismuth telluride thin films by hot wall epitaxy, thermoelectric properties

摘要

It is well known that bisumth telluride (Bi_2Te_3), its isomorphs (Bi_2Se_3 and Sb_2Te_3) and their alloys have the optimum bandgap (0.13 eV to 0.21 eV) for efficient solid state cooling applications around 300K. Recently interesting work argued that the use of quantum well structures can enhance the figure of merit ZT as a result of the improvement of carrier charge density of state and the reduction of the thermal conductivity. However, for the production of such structures it is necessary to establishe the optimum growth conditions and the doping levels of thin films based on Bi_2Te_3 and its isomorphs.