Electrical and optical properties of nanocrystalline yttrium-doped hafnium oxide thin films

Abstract Yttrium-doped hafnium oxide (YDH) films have been produced by sputter-deposition by varying the growth temperature (T s ) from room-temperature (RT) to 400 °C. The electrical and optical properties of YDH films have been investigated. Structural studies indicate that YDH films grown at T s = RT − 200 °C were amorphous and those grown at 300–400 °C are nanocrystalline. The crystalline YDH films exhibit the high temperature cubic phase of HfO 2 . Spectrophotometry analysis indicates that all the YDH films are transparent. The band gap of YDH films was found to be in the range of 6.20–6.28 eV. Frequency variation of frequency dependent resistivity indicates the hopping conduction mechanism operative in YDH films. While the electrical resistivity (ρ ac ) is ~ 1 Ω-m at low frequencies (100 Hz), ρ ac decreases to ~ 10 − 4 Ω-cm at higher frequencies (1 MHz).