Substrates for optical and electron microscopy of 2D materials

Patent metadata

Field	Value
Publication number	US-12463032-B2
Application number	US-202318119347-A
Country	US
Kind code	B2
Filing date	Mar 9, 2023
Priority date	Apr 16, 2022
Publication date	Nov 4, 2025
Grant date	Nov 4, 2025

Abstract

One or more embodiments relates to a substrate consisting of an ultrathin, conductive, shapeless metal oxide on SiO 2 /Si substrate. In one embodiment, the substrate facilitates experimental characterization of 2D materials simultaneously via optical identification of the single monolayer thickness of 2D materials and electron-based spectro-microscopy characterization.

First claim

What is claimed is:

1 . A method for providing an ultrathin, conductive, atomically flat, and amorphous metal oxide layer on a SiO 2 /Si substrate, the method comprising:
depositing the metal oxide layer on the SiO 2 /Si substrate forming a prepared substrate; and exfoliating a 2D material onto the prepared substrate wherein the combination of metal oxide layer and SiO 2 /Si substrate simultaneously enables the optical determination of the thickness of 2D materials and spectro-microscopic measurements.

2 . The method of claim 1 wherein the metal oxide layer is a titanium oxide (TiOx) layer.

3 . The method of claim 2 wherein the TiOx oxide layer ranges between about 1-10 nm in thickness.

4 . The method of claim 1 wherein the metal oxide layer is selected from a group comprising ZnO x , SnO x , InO x , VO x , Al-doped ZnO x (AZO), In-doped ZnO x (IZO), Ga-doped ZnO x (GZO), Zn-doped SnO x (ZTO), In-doped SnO x (ITO), In- and Ga-doped ZnO x (IGZO), alloys thereof; transitional metal dichalcogenide and tellurides.

5 . The method of claim 1 wherein the SiO 2 /Si substrate ranges between about 90-300 nm in thickness.

6 . The method of claim 1 , further comprising depositing the metal oxide layer on the SiO 2 /Si substrate at about 85° C.

7 . The method of claim 1 further comprising using a metal-based precursor titanium isopropoxide for deposition.

8 . The method of claim 1 further comprising using one or more metal-based precursors for deposition selected from a group comprising trimethylaluminum (TMA), diethyl zinc (DEZ), trimethyl gallium, trimethyl indium, tetrakis(diethylamido)tin, and tetrakis(diethylamido)titanium.

9 . The method of claim 1 , further comprising annealing the prepared substrate in a two-step process forming gas 4% H 2 in Ar at 400° C. for 15 minutes and 600° C. for 15 minutes.

10 . The method of claim 1 wherein depositing the metal oxide layer on the SiO 2 /Si substrate forming the prepared substrate comprises using a process selected from a group comprising atomic layer deposition (ALD), sputtering based physical vapor deposition, and solution-based spray pyrolysis.

11 . The method of claim 1 further comprising performing the spectro-microscopic measurements on features of interest and selected from a group comprising low-energy electron diffraction (LEED), low-energy microscopy (LEEM), x-ray photoemission spectroscopy (XPS), x-ray absorption spectroscopy (XAS) and angle-resolved photoemission (ARPES).

12 . The method of claim 1 further comprising the prepared substrate having patterned metal fiduciary structures for locating features of interest.

13 . The method of claim 1 , wherein the 2D material is selected from a group comprising graphene, transitional metal chalcogenide, hexagonal boron nitride, silicene, and carbene.

14 . A method for providing ultrathin, conductive, atomically flat, and amorphous titanium oxide (TiO x ) layer having a thickness ranging between about 1-10 nm in thickness on a SiO 2 /Si substrate having a thickness ranging between 90-300 nm thick, the method comprising:
depositing the TiO x on the SiO 2 /Si substrate using a process selected from a group comprising atomic layer deposition (ALD), sputtering based physical vapor deposition, and solution-based spray pyrolysis forming a prepared substrate; and exfoliating a 2D material onto the prepared substrate where the combination of TiO x layer and SiO 2 simultaneously enables the optical determination of the thickness of 2D materials, as well as performing spectro-microscopic measurements selected from a group comprising low-energy electron diffraction (LEED), low-energy microscopy (LEEM), x-ray photoemission spectroscopy (XPS), x-ray absorption spectroscopy (XAS) and angle-resolved photoemission (ARPES) which are performed on features of interest.

15 . The method of claim 14 , wherein one or more metal-based precursor selected from a group comprising titanium isopropoxide and tetrakis(diethylamido) titanium are used for deposition.

16 . The method of claim 14 , further comprising annealing the prepared substrate in a two-step process forming gas 4% H 2 in Ar at 400° C. for 15 minutes and 600° C. for 15 minutes.

17 . The method of claim 14 , wherein the 2D material is selected from a group comprising graphene, transitional metal chalcogenide, hexagonal boron nitride, silicene, and carbene.

18 . A method for imaging graphene exfoliated onto an ultrathin, conductive, atomically flat, and amorphous metal oxide layer on a SiO 2 /Si substrate, the method comprising:
forming a first probe of elemental particles comprising electrons (fermions) at very low energy ranging from (0 to 10 eV) in a backscattering setup; and forming a second probe of elemental particles comprising photons (bosons) having −E=2.3 eV and −λ=532 nm for inelastic photon-electron scattering in a confocal Raman spectro-microscope, wherein the first and second probes are used to image the electron-phonon coupling of the ultrathin, conductive, atomically flat, and amorphous metal oxide layer on a SiO 2 /Si substrate.

19 . The method of claim 18 wherein the graphene is selected from a group comprising single-layer graphene, bilayer graphene, and 30° twisted bilayer graphene (30°-tBLG).

20 . The method of claim 18 , wherein the interface studied can be graphene-TiO x heterostructure interface or graphene-graphene interface in either bilayer graphene or 30°-tBLG.

Assignees

• Us Energy
• Us Dept Energy

Inventors

• Sadowski Jerzy T
• Nam Chang-Yong
• Tiwale Nikhil
• Subramanian Ashwanth
• Dai Zhongwei
• Li Mingxing

Classifications

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P14/668

  the materials being characterised by the deposition precursor materials · CPC title

• H10P14/6339 Primary

  deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD · CPC title

• H10P14/20

  of semiconductor materials · CPC title

• H10P14/6334

  using decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition (deposition by physical ablation of a target H10P14/6329) · CPC title