Fractional photoconductivity glow curves of β-rhombohedral boron

The energy band structure of β-rhombohedral boron is characterized by multiple electron and hole traps in the band gap. Fractional photoconductivity glow experiments were performed between 170 and 360 K for obtaining further information on the various traps in this semiconductor. The results can easily be interpreted within the actual band scheme and confirm the previous assumption of a cascade-like recombination of optically excited electrons with an activation energy of about 0.12 eV. The result support the assumption of optically induced structural changes regarding the partly occupied sites B(13) and B(16) to B(20).