Controlled p-type to n-type conductivity transformation in NiO thin films by ultraviolet-laser irradiation

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3671412· OSTI ID:22038837

Gupta, Pranav; Dutta, Titas; Mal, Siddhartha; Narayan, Jagdish ^[1]

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1. Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27606 (United States)

We report the systematic changes in structural, electrical, and optical properties of NiO thin films on c-sapphire introduced by nanosecond ultraviolet excimer laser pulses. Epitaxial nature of as deposited NiO was determined by x-ray diffraction phi scans and transmission electron microscopy (TEM) and it was established that NiO film growth takes place with twin domains on sapphire where two types of domains have 60 deg. in-plane rotation with respect to each other about the [111] growth direction. We determined that at pulsed laser energy density of 0.275 J/cm{sup 2}, NiO films exhibited conversion from p-type semiconducting to n-type conductive behavior with three orders of magnitude decrease in resistivity, while maintaining its cubic crystal structure and good epitaxial relationship. Our TEM and electron-energy-loss spectroscopy studies conclusively ruled out the presence of any Ni clustering or precipitation due to the laser treatment. The laser-induced n-type carrier transport and conductivity enhancement were shown to be reversible through subsequent thermal annealing in oxygen. This change in conductivity behavior was correlated with the nonequilibrium concentration of laser induced Ni{sup 0}-like defect states.

• OSTI ID: 22038837
• Journal Information: Journal of Applied Physics, Vol. 111, Issue 1; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CRYSTAL GROWTH
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ENERGY DENSITY
ENERGY-LOSS SPECTROSCOPY
EPITAXY
EXCIMER LASERS
LASER RADIATION
NICKEL OXIDES
N-TYPE CONDUCTORS
OPTICAL PROPERTIES
PRECIPITATION
P-TYPE CONDUCTORS
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
ULTRAVIOLET RADIATION
X-RAY DIFFRACTION