Open AccessBand Alignment of Al2O3 on α-(AlxGa1-x)2O3
Author(s) -
Xinyi Xia,
Nahid Sultan Al-Mamun,
Chaker Fares,
Aman Haque,
F. Ren,
Anna Hassa,
Holger von Wenckstern,
Marius Grundmann,
S. J. Pearton
Publication year - 2022
Publication title -
ecs journal of solid state science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.488
H-Index - 51
eISSN - 2162-8777
pISSN - 2162-8769
DOI - 10.1149/2162-8777/ac546f
Subject(s) - materials science , band gap , semimetal , valence band , x ray photoelectron spectroscopy , valence (chemistry) , direct and indirect band gaps , analytical chemistry (journal) , spectroscopy , conduction band , crystallography , atomic physics , optoelectronics , physics , nuclear magnetic resonance , chemistry , electron , quantum mechanics , chromatography
X Ray Photoelectron Spectroscopy was used to measure valence band offsets for Al 2 O 3 deposited by Atomic Layer Deposition on α -(Al x Ga 1-x ) 2 O 3 alloys over a wide range of Al contents, x, from 0.26–0.74, corresponding to a bandgap range from 5.8–7 eV. These alloys were grown by Pulsed Laser Deposition. The band alignments were type I (nested) at x <0.5, with valence band offsets 0.13 eV for x = 0.26 and x = 0.46. At higher Al contents, the band alignment was a staggered alignment, with valence band offsets of − 0.07 eV for x = 0.58 and −0.17 for x = 0.74, ie. negative valence band offsets in both cases. The conduction band offsets are also small at these high Al contents, being only 0.07 eV at x = 0.74. The wide bandgap of the α -(Al x Ga 1-x ) 2 O 3 alloys makes it difficult to find dielectrics with nested band alignments over the entire composition range.