Electronic and optical properties of La‐aluminate dielectric thin films on Si (100)

Electronic and optical properties of (La 2 O 3 ) x (Al 2 O 3 ) 1− x thin films grown on Si(100) by the atomic layer deposition method were studied by means of reflection electron energy loss spectroscopy (REELS). The dielectric function ε( k , ω), index of refraction ( n ) and the extinction coefficient ( k ) for (La 2 O 3 ) x (Al 2 O 3 ) 1− x thin films were obtained from a quantitative analysis of REELS data. The band gap of (La 2 O 3 ) x (Al 2 O 3 ) 1− x thin films increases from 5.75 to 6.35 eV as the Al 2 O 3 content (1 − x ) increases from 0.5 to 0.75 in the compound. The optical properties described in terms of n , k , and ε of (La 2 O 3 ) x (Al 2 O 3 ) 1− x were obtained from REELS spectra by using QUEELS‐ε( k , ω)‐REELS software. They show that the electronic and optical properties of (La 2 O 3 ) x (Al 2 O 3 ) 1− x thin films are dominated by La 2 O 3 even for high Al 2 O 3 concentrations. Copyright © 2010 John Wiley & Sons, Ltd.