Van der Waals Heterostructures with Tunable Tunneling Behavior Enabled by MoO₃ Surface Functionalization

Abstract

Heterostructures of 2D materials represent a powerful material platform that has essentially defined the technological foundation for all modern electronic and optoelectronic devices. Although most of the reported heterostructures devices exhibit extraordinary electronic and optoelectronic properties, they depend on the proper combination of selected materials, which limits the broad tunability of the devices. Herein, it is demonstrated that a vertical van der Waals heterostructures (vdWHs) device, which is composed of MoS2 and MoTe2, can function as a backward tunneling diode, photovoltaic cell, and photodetector through surface functionalization of MoO3. The realization of this backward tunneling diode is attributed to the band alignment variation from type II to type III via in situ MoO3 functionalization. Furthermore, the power conversion efficiency of this vdWHs based photovoltaic device is significantly enhanced by nearly four times, benefiting from the more efficient photocarrier separation after MoO3 decoration. The enhanced photovoltaic effect can be retained even after air exposure, revealing the excellent air stability. Meanwhile, the modified vdWHs device exhibits the photodetecting property with photocurrent responsivity of around 2 A W−1 and external quantum efficiency about 400%. This work promises surface functionalization as an effective approach to broaden the device functionality of 2D heterostructures in electronics and optoelectronics.

Band‐tailored van der Waals heterostructure for multilevel memory and artificial synapse

“…ln( I ) is proportional to V b 1/2 with a positive slope described by the Richardson‐Schottky (RS) model (Region I), implying a thermionic emission (TE) process 41 . When V b crosses over V th (Region II), Fowler−Nordheim (FN) tunneling gradually dominates in the large voltage region, which is corroborated by the appearance of a negative linear slope in the FN plot, as shown in Figure 2(C) 42 . The corresponding fitting results in the negative V b region are shown in Figure S10, which also reveals a similar transport evolution process.…”

Two-Dimensional Field-Effect Transistor Sensors: The Road toward Commercialization

“…Since the first case of exfoliation of graphene in 2004, researchers have developed a broad variety of 2D material families, which include graphene and reduced graphene oxide (rGO), − TMDs, − III–VI compounds, , MXenes, , elemental 2D materials, , 2D organic materials, , 2D nitrides, synthetic 2D metal hydrides, and 2D metal oxides, , just to name a few. − Here, we briefly introduce 2D channel materials used in the FET sensors.…”

Ambipolar‐To‐Unipolar Conversion in Ultrathin 2D Semiconductors

“…For example, organics containing -NH 2 , such as (3 aminopropyls) triethoxysilane (APTES), hydrazine, ethanolamine (MEA), polyethylenimine (PEI), are commonly utilized as n-type dopants because -NH 2 possesses lengthy electron pairs to remove holes from the host material. [47] Organics containing -CH 3 , such as octadecyl trichlorosilane (OTS), is often utilized as p-dopants because the Nb [46] H 2 O, O 2 , [52] NO 2 [53] 4-NBD, [54] F4 -TCNQ-PMMA, [55] OTS; [56] M-DNA [57] MoO 3 ; [58] WOx [59] AuCl 3 ; [60] Pt [61] S; [39] Re [46] N 2 H 4 [62] PPH 3 , [63] DETA [54] [RuCp*(mes)], [64] DNA; [57] Cs 2 CO 3 [65] K [66] MoTe 2 Nb [67] O 2 ; [53] H 2 O [68] TCNQ [69] MoO 3 [70] -Sb; [71] Re [72] N 2 H 4 [64] BV; [53] HAT-CN [73] MgO [74] Al [75] Phosphorene (BP)…”