Hole-majority condition in thin films of semimetal bismuth

Experimental evidence suggested that the charge-neutrality condition in thi n films of semimetal bismuth may be violated due to energy band distortion and that holes are the majority charge carriers. We have made calculations of the electron and hole densities, the Fermi energy, and the electric cond uctivity as functions of the film thickness and the temperature, using a ho le-majority model in contrast to previous work of this kind. Results are pr esented and they are in fairly good agreement with existing experimental da ta. The electron density would go down to zero at zero temperature in suffi ciently thin films leading to a "semimetal-semiconductor" transition. Two d ifferent boundary conditions that size quantize the energy spectra have bee n alternately employed and results compared. The quantum-mechanical backgro und of the boundary conditions has been discussed.