Carrier multiplication (CM) is the process of generating multiple electron-hole pairs from one absorbed photon. Narrow-gap InN is a material that has been proposed for achieving efficient CM. We quantify the CM efficiency in bulk InN using terahertz time-domain spectroscopy. While the CM onset occurs at relatively low photon energies in InN (1.7 ± 0.2 eV), corresponding to 2.7 ± 0.3 times its bandgap, the excitation efficiency above the onset increases linearly with a slope of only ∼13%/Eg. Based on these numbers, the efficiency increase of an InN based photovoltaic device owing to CM is limited to maximum 1% point.

Appl. Phys. Lett.

Jensen, S. A., Versluis, J., Cánovas, E., Pijpers, J. J. H., Sellers, I. R., & Bonn, M. (2012). Carrier multiplication in bulk indium nitride. Appl. Phys. Lett., 101(Article number: 222113), 1–4. doi:10.1063/1.4766738