n- and p-Type Doping Phenomenon by Artificial DNA and M-DNA on Two-Dimensional Transition Metal Dichalcogenides

Abstract

Deoxyribonucleic acid (DNA) and two-dimensional (2D) transition metal dichalcogenide (TMD) nanotechnology holds great potential for the development of extremely small devices with increasingly complex functionality. However, most current research related to DNA is limited to crystal growth and synthesis. In addition, since controllable doping methods like ion implantation can cause fatal crystal damage to 2D TMD materials, it is very hard to achieve a low-level doping concentration (nondegenerate regime) on TMD in the present state of technology. Here, we report a nondegenerate doping phenomenon for TMD materials (MoS2 and WSe2, which represent n- and p-channel materials, respectively) using DNA and slightly modified DNA by metal ions (Zn(2+), Ni(2+), Co(2+), and Cu(2+)), named as M-DNA. This study is an example of interdisciplinary convergence research between DNA nanotechnology and TMD-based 2D device technology. The phosphate backbone (PO4(-)) in DNA attracts and holds hole carriers in the TMD region, n-doping the TMD films. Conversely, M-DNA nanostructures, which are functionalized by intercalating metal ions, have positive dipole moments and consequently reduce the electron carrier density of TMD materials, resulting in p-doping phenomenon. N-doping by DNA occurs at ∼6.4 × 10(10) cm(-2) on MoS2 and ∼7.3 × 10(9) cm(-2) on WSe2, which is uniform across the TMD area. p-Doping which is uniformly achieved by M-DNA occurs between 2.3 × 10(10) and 5.5 × 10(10) cm(-2) on MoS2 and between 2.4 × 10(10) and 5.0 × 10(10) cm(-2) on WSe2. These doping levels are in the nondegenerate regime, allowing for the proper design of performance parameters of TMD-based electronic and optoelectronic devices (VTH, on-/off-currents, field-effect mobility, photoresponsivity, and detectivity). In addition, by controlling the metal ions used, the p-doping level of TMD materials, which also influences their performance parameters, can be controlled. This interdisciplinary convergence research will allow for the successful integration of future layered semiconductor devices requiring extremely small and very complicated structures.

Recent Advances in Doping of Molybdenum Disulfide: Industrial Applications and Future Prospects

“…On the contrary, since M–DNA with metal ions have positive dipole moments for reducing the electrons in MoS 2 (or WSe 2 ), consequently, M–DNA induces p‐doping of MoS 2 films. The low level of n‐doping achieved by DNA on MoS 2 films (≈6.4 × 10 10 ) was confirmed by Raman spectroscopy and electrical characteristics ( I D – V G ) measurement . The p‐doping concentrations for M–DNA were between 2.3 × 10 10 and 5.5 × 10 10 cm −2 on MoS 2 .…”

“…DNA doping is an exotic doping technique for TMDs which combines biomedical technology and nanotechnology . In 2014, Park et al presented synthesis techniques of artificial‐DNA and M–DNA (metal–DNA is the DNA modified by metal ions; Zn 2+ , Ni 2+ , Co 2+ , or Cu 2+ ) and their doping of MoS 2 .…”

“…In 2014, Park et al presented synthesis techniques of artificial‐DNA and M–DNA (metal–DNA is the DNA modified by metal ions; Zn 2+ , Ni 2+ , Co 2+ , or Cu 2+ ) and their doping of MoS 2 . Investigation of DNA‐based doping of MoS 2 using the artificial‐DNA (n‐type) and M–DNA (p‐type) showed a nondegenerate doping phenomenon on MoS 2 films ( Figure ) . It is thought that the PO 4 − sites in DNA backbones hold hole carriers at the DNA‐MoS 2 interface region, thereby inducing n‐type doping of MoS 2 layers.…”

“…g) Photoresponsivity and h) detectivity of MoS 2 photodetector as a function of V GS – V th (in off‐state). Reproduced with permission . Copyright 2014, The American Chemical Society.…”

Band Structure Engineering in 2D Materials for Optoelectronic Applications

“…Similar to graphene, the Fermi level of the TMD monolayers can also be tuned with an external electric field or chemical doping. Several studies have investigated the surface charge transfer doping effects on atomically thin TMDs . The doping level can simply be monitored with the variation of the photoluminescence (PL) spectra and the change in carrier transport behavior.…”