InN films with In and N polarities grown by molecular beam epitaxy are studied by photoreflectance (PR). No PR feature is observed at 293 K. At 50 K, for N-polar InN, a broad PR feature with Franz-Keldysh oscillations (FKOs) is observed. The surface electric field (312 kV/cm) and band gap (0.682 eV) are deduced from analyzing FKO extremes. However, some narrow PR features are observed for In-polar InN and three transition energies are obtained, but no FKO is observed. These indicate that the surface electric field (or surface band bending) of In-polar InN is smaller than that of N-polar InN.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)