ENGINEERING ZnO/GaN INTERFACES FOR TUNNELING OHMIC CONTACTS TO GaN

ABSTRACT We have investigated two approaches for the fabrication of thin ZnO films: sputter deposition from the ZnO target and thermal oxidation of vacuum deposited Zn. The microstructure and electronic properties after consecutive steps of the formation of n-ZnO/pGaN contacts have been studied using electron transmission microscopy and x-ray photoelectron spectrometry. We have achieved ohmic contacts by Zn oxidation and explain their ohmic behaviour in terms of a tunnel n + -ZnO -p-GaN junction

Technology of Ultrathin NbN and NbTiN Films for Superconducting Photodetectors

We report fabrication and characterization of ultrathin NbN and NbTiN films designed for superconducting photodetectors. Our NbN and NbTiN films were deposited on $Al_2O_3$ and Si single-crystal wafers by a high-temperature, reactive magnetron sputtering method and, subsequently, annealed at 1000°C. The best, 18 nm thick NbN films deposited on sapphire exhibited the critical temperature of 15.0 K and the critical current density as high as ≈ 8 × $10^6$ A/$cm^2$ at 4.8 K

Transparent ZnO-based ohmic contact to p-GaN

Highly conductive ZnO films were fabricated on p-GaN in a two-step process. First, zinc was thermally evaporated on p-GaN. Next, zinc film was oxidized in oxygen flow. To increase the conductivity of ZnO, nitrogen was introduced into zinc during its deposition. The above procedure proved successful in fabricating ZnO of the resistivity of {approx}1 x 10{sup -3} {Omega}cm and resulted in ohmic contacts of resistivity {approx}1 x 10{sup -2} {Omega}cm{sup 2} to low-doped p-GaN, and light transmittance of {approx}75% in the wavelength range of 400-700 nm

Transparent ZnO-based ohmic contact to p-GaN

Highly conductive ZnO films were fabricated on p-GaN in a two-step process. First, zinc was thermally evaporated on p-GaN. Next, zinc film was oxidized in oxygen flow. To increase the conductivity of ZnO, nitrogen was introduced into zinc during its deposition. The above procedure proved successful in fabricating ZnO of the resistivity of {approx}1 x 10{sup -3} {Omega}cm and resulted in ohmic contacts of resistivity {approx}1 x 10{sup -2} {Omega}cm{sup 2} to low-doped p-GaN, and light transmittance of {approx}75% in the wavelength range of 400-700 nm