Hybrid Modulation‐Doping of Solution‐Processed Ultrathin Layers of ZnO Using Molecular Dopants

Abstract

An alternative doping approach that exploits the use of organic donor/acceptor molecules for the effective tuning of the free electron concentration in quasi‐2D ZnO transistor channel layers is reported. The method relies on the deposition of molecular dopants/formulations directly onto the ultrathin ZnO channels. Through careful choice of materials combinations, electron transfer from the dopant molecule to ZnO and vice versa is demonstrated.

N-Doping improves charge transport and morphology in the organic non-fullerene acceptor O-IDTBR

“…Finally, we find that N-DMBI only acts as an n-dopant when it loses an H-atom and transfers a hydrogen anion to the O-IDTBR (Figure 4c), following the hydride transfer mechanism described previously. 21,44 However, we do note that, although the findings in our DFT results are substantiated throughout the literature, there are more recent, spectroscopic findings that exclude hydride transfer as a doping mechanism for N-DMBI-based systems, and rather support mechanisms of electron transfer between an electron acceptor and a donor 45 . Overall, the DFT results show the three dopants appear to n-dope the O-IDTBR via different mechanisms, with each dopant altering the electronic structure of O-IDTBR differently.…”

“…13 Other n-dopants -that utilise alternative doping mechanisms -have also been identified in the literature, with two exemplary materials being tetra-n-butylammonium fluoride (TBAF) (Figure 1b), 12,19,20 and 4-(2,3-dihydro-1,3-dimethyl-1H-benzimidazol-2-yl)-N,Ndimethylbenzenamine (N-DMBI) (Figure 1c). 21,22,14 To test the applicability of DMBI-BDZC, TBAF and N-DMBI as n-dopants in O-IDTBR, we studied each system using EPR. The latter technique can be used to detect whether free charge carriers have been generated in a system with the addition of a dopant; 23,24 if such fundamental exchange mechanisms exist between host and dopant, an increase in EPR signal is expected.…”

An all-solid-state heterojunction oxide transistor for the rapid detection of biomolecules and SARS-CoV-2 spike S1 protein

“…In2O3 exhibits the lowest peak-to-peak height (Z) of 1.87 nm with a root-mean-square roughness (RMS) value of 0.20 nm, which are comparable to that of SiO2 (Z = 1.91 nm, RMS = 0.21 nm). Subsequent deposition of ZnO atop In2O3 leads to a slightly rougher topography (Z = 4.00 nm, RMS = 0.58 nm) indicative of a more textured surface 31,34 .…”

Molecule Charge Transfer Doping for p‐Channel Solution‐Processed Copper Oxide Transistors

“…Unlike conventional atomic substitution doping, the doping process does not induce any defects or impurities into the host lattice, thereby eliminating undesired carrier scattering while reserving the fundamental transport properties. [ 11 ] Originally, MCTD was mainly used with organic semiconductors [ 12,13 ] and recently has been extended to n‐type metal oxides [ 14,15 ] and low‐dimensional nanomaterials (2D semiconductors, [ 16 ] carbon nanotubes, [ 17,18 ] and nanocrystals [ 19 ] ). For p‐type MCTD doping, the dopants should have a higher electron affinity than that of the host materials; commonly used candidates are MoO 3 , NO 2 , and tetrafluoro‐tetracyanoquinodimethane (F 4 TCNQ).…”