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Sol–gel prepared (Ga 1− x In x ) 2 O 3 thin films for solar‐blind ultraviolet photodetectors
Author(s) -
Kokubun Yoshihiro,
Abe Torataro,
Nakagomi Shinji
Publication year - 2010
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200983712
Subject(s) - indium , materials science , thin film , absorption edge , analytical chemistry (journal) , sapphire , gallium , band gap , monoclinic crystal system , absorption (acoustics) , photoconductivity , optoelectronics , optics , crystallography , chemistry , crystal structure , nanotechnology , laser , physics , chromatography , metallurgy , composite material
We prepared (Ga 1− x In x ) 2 O 3 thin films at 900 °C using a sol–gel method, from a 2‐methoxyethanol solution of gallium isopropoxide and indium isopropoxide stabilized by monoethanolamine on (0001) sapphire substrates. X‐ray diffraction showed that films prepared from solutions with an indium content below 0.4 are single phase with the same monoclinic structure as β‐Ga 2 O 3 and that increasing the indium content increases the lattice constants. Optical absorption showed that the band gap decreased linearly to 4.2 eV as indium content increased to 0.3. Planar geometry photoconductive detectors have been fabricated on the (Ga 1− x In x ) 2 O 3 thin films prepared from the solution with an indium content below 0.2. They showed photosensitivity in the solar‐blind region, and the long wavelength threshold of spectral response shifted toward longer wavelengths with an increasing indium content. Furthermore, heterojunction structures composed of Ga 2 O 3 and (Ga 1− x In x ) 2 O 3 were also fabricated and characterized by transmission electron microscopy and optical absorption.