An observation of photoconductivity in a homonuclear semimetal (bismuth) is reported. The effect is observed when bismuth films of different thicknesses are irradiated with 1.064-μm laser pulses. The sign and the temporal evolution of the resistivity change induced in the films are studied. An anomalous resistivity change due to laser heating is observed in the thickest film. A theoretical interpretation that explains and fits the experimental behavior well is given. The results support the predictions of a previously reported model that required the pumping of carriers into a metastable band by the laser light. The sum of the mobilities and of the diffusion coefficients for electrons and holes in this band are also estimated.

• Received 25 February 1994

DOI:https://doi.org/10.1103/PhysRevB.50.1861