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Tailoring the Band Alignment of Ga x Zn 1‐x O/InGaZnO Heterojunction for Modulation‐Doped Transistor Applications
Author(s) -
Zhang YiYu,
Qian LingXuan,
Ge WanBing,
Lai PuiTo,
Liu XingZhao
Publication year - 2018
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.201800332
Subject(s) - heterojunction , band bending , materials science , x ray photoelectron spectroscopy , band offset , doping , optoelectronics , band diagram , band gap , conduction band , electronic band structure , valence band , electron , condensed matter physics , physics , nuclear magnetic resonance , quantum mechanics
In this work, the band alignments of G x Z 1‐x O y /a‐IGZO heterojunctions with different Ga contents (x) are investigated by X‐ray photoelectron spectroscopy (XPS). It is found that for increasing Ga content, the valence‐band offset is monotonically reduced, whereas the conduction‐band offset is continuously increased. Moreover, the band alignment changes from type I to II. The variation of band alignment is mainly attributed to the band bending at the interface of the heterojunction, which can be traced back to oxygen vacancies for higher Ga content, rather than enlarged bandgap. As a result, G 0.47 Z 0.53 O 1.14 /a‐IGZO heterojunction exhibites a more ideal band alignment structure, which can favor the formation of two‐dimensional electron gas. In summary, it is found that the band alignment of G x Z 1‐x O y /a‐IGZO heterojunction can be effectively tailored by its Ga content, thus providing a method to achieve high‐performance a‐IGZO‐based modulation‐doped transistors.