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Pentacene memory transistors with a monolayer of ligand‐removed semiconductor colloidal nanodots used as a charge‐trapping layer
Author(s) -
Nakano Fumihoru,
Uno Kazuyuki,
Tanaka Ichiro
Publication year - 2017
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.201600545
Subject(s) - pentacene , homo/lumo , materials science , monolayer , transistor , semiconductor , optoelectronics , trapping , thin film transistor , active layer , layer (electronics) , molecule , nanotechnology , chemistry , voltage , organic chemistry , physics , biology , ecology , quantum mechanics
We fabricated pentacene memory transistors of which floating gate or charge‐trapping layer consisted of monolayer of PbS colloidal nanodots (NDs), and investigated their writing and retention characteristics. Both of the writing and retention times of the pentacene memory transistors were significantly reduced when the ligand molecules (oleic acid) were removed. We also found that the writing time was further reduced and the retention time was extended by using larger NDs, in which the quantized energy level in the conduction band was lower, that is, closer to the highest occupied molecular orbital (HOMO) and farther from the lowest unoccupied molecular orbital (LUMO) of the pentacene. These results are explained with a model that the memory effect is due to the trapped electrons in the NDs after a positive writing voltage is applied on the control gate, and suggest that more suitable arrangement of the quantized energy level in the NDs and HOMO/LUMO levels in organic molecules would improve the characteristics of the memory transistors.