Open AccessEffects of Al2O3 Capping and Post-Annealing on the Conduction Behavior in Few-Layer Black Phosphorus Field-Effect Transistors
Author(s) -
H. M. Zheng,
J. Gao,
S. M. Sun,
Q. Ma,
Y. P. Wang,
B. Zhu,
W. J. Liu,
H. L. Lu,
S. J. Ding,
David W. Zhang
Publication year - 2018
Publication title -
ieee journal of the electron devices society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.69
H-Index - 31
ISSN - 2168-6734
DOI - 10.1109/jeds.2018.2804481
Subject(s) - components, circuits, devices and systems , engineered materials, dielectrics and plasmas
Ambient instability has been proven challenging in black phosphorus field-effect transistors (BP FETs) and a capping layer is thus needed for their practical applications. In this paper, we have examined the effects of Al2O3 capping and O2 post-annealing on the conduction characteristic of BP FETs. With the Al2O3 capping, it forms p-type into ambipolar transport and the electron mobility dramatically increases to 20-110 cm2/V·s in our case. Interestingly, with the O2 post-annealing, the transport can be tuned from ambipolar back to p-type as the annealing time extends. It is attributed that the Al2O3 capping introduces an n-type doping in BP channel while the O2 post-annealing dopes BP back into p-type. Moreover, after the O2 post-annealing the interfacial POx might be formed, resulting in the degradation of subthreshold swing and on/off current ratio.