Determination of surface barrier height and surface state density in GaN films grown on sapphire substrates
Seong-Eun Park, Joseph Kopanski, Youn-Seon Kang, Larry Robins, Hyun-Keel Shin
Photoreflectance (PR) modulation spectroscopy was performed to investigate surface properties of GaN films grown on sapphire substrates. From the period of the Franz-Keldysh oscillations, the surface electric field across the GaN space charge region was found to be (197.3 '' 11.4) kV/cm, which corresponds to a surface state density of 1.0 x 10e12 cm^-2. A surface barrier height (SBH) of 0.71 eV was determined by fitting the dependence of the PR intensities on pump beam power density. We suggest that a deep level is formed at 2.68 eV above the GaN valence band edge due to the large density of surface states.
, Kopanski, J.
, Kang, Y.
, Robins, L.
and Shin, H.
Determination of surface barrier height and surface state density in GaN films grown on sapphire substrates, MRS Electronic Proceedings, Boston, MA, USA
(Accessed December 8, 2023)