Laser-Written Submicron Pixels with Tunable Circular Polarization and Write-Read-Erase-Reuse Capability on a Nano Material or Two-Dimensional Heterostructure at Room Temperature

Abstract

A method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on Bi.sub.2Se.sub.3/WS.sub.2 at room temperature, comprising the steps of applying a laser to the Bi.sub.2Se.sub.3/WS.sub.2, writing a submicron pixel, wherein the submicron pixel has a circular polarization, modifying the circular polarization, allowing the circular polarization to be tuned across a range of 39.9%, tuning photoluminescence intensity, and tuning photoluminescence peak position. A method of growing Bi.sub.2Se.sub.3/WS.sub.2 as a nano-material or two-dimensional heterostructure for laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on the Bi.sub.2Se.sub.3/WS.sub.2 heterostructure at room temperature.

Claims

1. A method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature, comprising the steps of: applying a laser to a nano-material or two-dimensional heterostructure; writing a submicron pixel; wherein the submicron pixel has a circular polarization; modifying the circular polarization; allowing the circular polarization to be tuned across a range of 39.9%; tuning photoluminescence intensity across a factor of 161 times; and tuning photoluminescence peak position across a range of 38 meV.

2. The method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 1 wherein the nano-material or two-dimensional heterostructure comprises Bi.sub.2Se.sub.2.

3. The method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 2, comprising the additional steps of: applying the laser in an atmosphere absent of oxygen; tuning the circular polarization; tuning the photoluminescence intensity; tuning the photoluminescence peak position; and enabling the material to be controllably erased and changes reversed.

4. The method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 3 wherein the nano-material or two-dimensional heterostructure comprises Bi.sub.2Se.sub.3/WS.sub.2 and wherein the nano-material or two-dimensional heterostructure is reusable.

5. The method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 4 wherein the steps occur at room temperature.

6. The method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 5 wherein the laser is a low-power laser.

7. The method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 6 wherein the laser comprises 0.60 micro Watts; wherein the laser written submicron pixels are written at 814 nm resolution; wherein the tuning is stable for greater than 106 days; and wherein the thickness of the SiO.sub.2 is 275 nm.

8. The method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 7 wherein increasing the laser power increases speed at which the changes are induced.

9. The method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 2, further comprising the step of: providing an oxygen environment; wherein the pixels are written with submicron resolution using a laser in the oxygen environment.

10. The method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 9, wherein the pixels are written at 814 nm resolution; wherein the tuning is stable for greater than 334 days; and wherein the thickness of the SiO.sub.2 is 275 nm.

11. A method of growing a nano-material or two-dimensional heterostructure for laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on the nano-material or two-dimensional heterostructure at room temperature, comprising the steps of: providing SiO.sub.2/Si substrates; cleaning the SiO.sub.2/Si substrates in acetone, IPA, and Piranha etch; rinsing the SiO.sub.2/Si substrates in deionized water; positioning at the center of a furnace a first quartz boat containing about 1 g of WO.sub.3 powder; positioning a first SiO.sub.2/Si substrate face-down, directly above the WO.sub.3 powder; positioning a second quartz boat containing sulfur powder upstream, outside the furnace-heating zone, for the synthesis of WS.sub.2; positioning a second SiO.sub.2/Si substrate above the second quartz boat; wherein the second SiO.sub.2/Si substrate contains perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS) seeding molecules; wherein the first SiO.sub.2/Si substrate is untreated; allowing the PTAS seeding molecules to be carried downstream to the first substrate which is untreated; promoting lateral growth of a monolayer WS.sub.2; utilizing pure argon at 65 sccm as the furnace heats to a target temperature; heating the furnace to a temperature of 825° C.; adding 10 sccm H.sub.2 to the Ar flow and maintaining; cooling to room temperature; and resulting in a monolayer WS.sub.2.

12. The method of growing a nano-material or two-dimensional heterostructure for laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on the nano-material or two-dimensional heterostructure at room temperature of claim 11, further comprising the steps of: growing a layer of Bi.sub.2Se.sub.3 on top of the monolayer of WS.sub.2 using chemical vapor deposition (CVD) in a two-zone furnace with a 2″ quartz tube; wherein the step of growing a layer of Bi.sub.2Se.sub.3 on top of the monolayer of WS.sub.2 using chemical vapor deposition (CVD) in a two-zone furnace with a 2″ quartz tube comprises the steps of grinding High-purity Bi.sub.2Se.sub.3 flakes into a fine dust; placing in a ceramic boat the fine dust of Bi.sub.2Se.sub.3; inserting the ceramic boat into the quartz tube; pushing the ceramic boat into the center of the first zone of the furnace; placing the monolayer WS.sub.2, which is on an SiO.sub.2 substrate, downstream of the Bi.sub.2Se.sub.3 into the center of the second zone of the furnace; pumping down the furnace to ˜20 mTorr; flowing an argon (Ar) carrier gas into the furnace at 80 sccm; heating the Bi.sub.2Se.sub.3 to a temperature of 520° C.; heating the WS.sub.2 to a temperature of 210° C.; heating at a ramp rate of ˜55° C./min; and growing Bi.sub.2Se.sub.3/WS.sub.2 for 27 min.

13. The method of growing a nano-material or two-dimensional heterostructure for laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 12 wherein 1-3 layers of Bi.sub.2Se.sub.3 is grown on the monolayer WS.sub.2 using CVD; and wherein the WS.sub.2 grows crystalline.

14. The method of growing a nano-material or two-dimensional heterostructure for laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 13 wherein the Bi.sub.2Se.sub.3/WS.sub.2 2D heterostructure comprises complete coverage of Bi.sub.2Se.sub.3 on the WS.sub.2.

15. The method of growing a nano-material or two-dimensional heterostructure for laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature of claim 14 wherein monolayer Bi.sub.2Se.sub.3 flakes several microns in size were grown on the monolayer WS.sub.2; wherein both the Bi.sub.2Se.sub.3 and the WS.sub.2 have long-range crystallinity; wherein the Bi.sub.2Se.sub.3 flakes or crystals grow at a 0° twist angle as the most stable configuration; and wherein the interlayer interaction modulates the growth.

16. A method of laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature, comprising the steps of: applying a laser to a nano-material or two-dimensional heterostructure; writing a submicron pixel; wherein the submicron pixel has a circular polarization; modifying the circular polarization; allowing the circular polarization to be tuned across a range of 39.9%; tuning photoluminescence intensity across a factor of 161 times; and tuning photoluminescence peak position across a range of 38 meV. wherein the nano-material or two-dimensional heterostructure comprises Bi.sub.2Se.sub.3/WS.sub.2.

17. A nano-material or two-dimensional heterostructure for laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on the nano-material or two-dimensional heterostructure at room temperature, formed by the steps of: providing SiO.sub.2/Si substrates; cleaning the SiO.sub.2/Si substrates in acetone, IPA, and Piranha etch; rinsing the SiO.sub.2/Si substrates in deionized water; positioning at the center of a furnace a first quartz boat containing about 1 g of WO.sub.3 powder; positioning a first SiO.sub.2/Si substrate face-down, directly above the WO.sub.3 powder; positioning a second quartz boat containing sulfur powder upstream, outside the furnace-heating zone, for the synthesis of WS.sub.2; positioning a second SiO.sub.2/Si substrate above the second quartz boat; wherein the second SiO.sub.2/Si substrate contains perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS) seeding molecules; wherein the first SiO.sub.2/Si substrate is untreated; allowing the PTAS seeding molecules to be carried downstream to the first substrate which is untreated; promoting lateral growth of a monolayer WS.sub.2; utilizing pure argon at 65 sccm as the furnace heats to a target temperature; heating the furnace to a temperature of 825° C.; adding 10 sccm H.sub.2 to the Ar flow and maintaining; cooling to room temperature; and resulting in a monolayer WS.sub.2.

18. The nano-material or two-dimensional heterostructure for laser-writing submicron pixels with tunable circular polarization and write-read-erase-reuse capability on the nano-material or two-dimensional heterostructure at room temperature of claim 17, further comprising the steps of: growing a layer of Bi.sub.2Se.sub.3 on top of the monolayer of WS.sub.2 using chemical vapor deposition (CVD) in a two-zone furnace with a 2″ quartz tube; wherein the step of growing a layer of Bi.sub.2Se.sub.3 on top of the monolayer of WS.sub.2 using chemical vapor deposition (CVD) in a two-zone furnace with a 2″ quartz tube comprises the steps of grinding High-purity Bi.sub.2Se.sub.3 flakes into a fine dust; placing in a ceramic boat the fine dust of Bi.sub.2Se.sub.3; inserting the ceramic boat into the quartz tube; pushing the ceramic boat into the center of the first zone of the furnace; placing the monolayer WS.sub.2, which is on an SiO.sub.2 substrate, downstream of the Bi.sub.2Se.sub.3 into the center of the second zone of the furnace; pumping down the furnace to ˜20 mTorr; flowing an argon (Ar) carrier gas into the furnace at 80 sccm; heating the Bi.sub.2Se.sub.3 to a temperature of 520° C.; heating the WS.sub.2 to a temperature of 210° C.; heating at a ramp rate of ˜55° C./min; and growing Bi.sub.2Se.sub.3/WS.sub.2 for 27 min.

19. A laser-writing submicron pixel with tunable circular polarization and write-read-erase-reuse capability on a nano-material or two-dimensional heterostructure at room temperature, formed by the steps of: applying a laser to a nano-material or two-dimensional heterostructure; wherein the nano-material or two-dimensional heterostructure comprises Bi.sub.2Se.sub.3/WS.sub.2; wherein the submicron pixel has a circular polarization; modifying the circular polarization; allowing the circular polarization to be tuned across a range of 39.9%; wherein photoluminescence intensity can be tuned across a factor of 161 times; and wherein photoluminescence peak position can be tuned across a range of 38 meV.

Description

DESCRIPTION OF THE DRAWINGS

[0056] The following description and drawings set forth certain illustrative implementations of the disclosure in detail, which are indicative of several exemplary ways in which the various principles of the disclosure may be carried out. The illustrated examples, however, are not exhaustive of the many possible embodiments of the disclosure. Other objects, advantages and novel features of the disclosure will be set forth in the following detailed description when considered in conjunction with the drawings.

[0057] FIG. 1 illustrates an As-Grown Bi.sub.2Se.sub.3/WS.sub.2 2D Heterostructure. A Schematic of the Bi.sub.2Se.sub.3/WS.sub.2 2D Heterostructure. Monolayer WS.sub.2 is grown using chemical vapor deposition (CVD) on a SiO.sub.2/Si substrate. 1-3 Layers of Bi.sub.2Se.sub.3 are then grown on top of the monolayer WS.sub.2 using CVD. Representative optical image, and atomic force microscopy (AFM) scan of the 2D heterostructure. The AFM scan shows near complete coverage Bi.sub.2Se.sub.3. A majority is bilayer Bi.sub.2Se.sub.3 coverage with islands of trilayer, and gaps of monolayer.

[0058] FIG. 2 is a Transmission Electron Microscope (TEM) imaging and diffraction of a Bi.sub.2Se.sub.3/WS.sub.2 2D Heterostructure. Imaging and diffraction measurements showing Bi.sub.2Se.sub.3 grows crystalline and at a 0° twist angle (i.e., aligned with the WS.sub.2).

[0059] FIG. 3 illustrates Low-Power Laser Writes Pixels and Patterns. Schematic of setup. Oxygen is required to induce changes in an as-grown sample. Optical image and fluorescence image of a Bi.sub.2Se.sub.3/WS.sub.2 2D heterostructure patterned with the letter “N” using a laser. The exposure time determines the luminescence intensity. Submicron (814 nm) pixel resolution is demonstrated. PL spectra of as-grown 2D heterostructure, and numerous spectra at different laser-exposure times. The PL spectra increases ×39.8, and the peak shifts 13.6 meV. Guide to the eye highlights the nonlinear evolution of the PL peak position, initially shifting higher in energy, before reversing and shifting lower in energy. The contrast, brightness, and sharpness of the optical image were adjusted to better reveal the color changes.

[0060] FIG. 4 illustrates Representative Lorentzian (and Background) Fitting for Intensity and Peak Position Extraction. The PL intensity and peak position are quantitively extracted with low error by fitting them with a Lorentzian function and a linear background. The resulting function consistently produces a good fit across different data sets and samples. Robust fitting ensures that the global minima is found with low error.

[0061] FIG. 5 illustrates Photoluminescence intensity and peak position can be tuned with high resolution. PL intensity, and peak position shift in response to continuous exposure of a low-power (0.60 μW) 532 nm laser. Each data point is extracted using robust fitting of the PL spectrum (see FIG. 3). The intensity increases a factor of ×39.8 over 280 measurements, before plateauing and slightly decreasing. The PL peak position shifts upward, and then decreases 13.6 meV over 254 measurements. The PL intensity and peak position evolution are smooth, containing low error and low noise. Lastly, the large number of spectra taken demonstrate the possibility for high-resolution and precise tuning. Error bars are present, but cannot be seen because they are smaller than the marker size.

[0062] FIG. 6 illustrates Laser-Tunable and Spatially-Selectable Circular Polarization at Room Temperature. PL intensity, PL peak position, and degree of circular polarization (DoCP) when intermittently exposed to a low-power (13.5 μW) σ+ circular polarized 588 nm laser. The intensity increases a factor of ×161, and plateaus, before slightly decreasing. Inset: the photon counts plotted logarithmically better display the initial data points. The PL peak position decreases 38.4 meV. Inset: A clear energy difference between the (++) and (+−) states provides guidance into the intervalley scattering mechanism, suggesting energy is lost when the exciton scatters to the opposing valley. The circular polarization shifts 39.9%. The large circular polarization shift shows the large range the material can be tuned. All experiments were done at room temperature, making it attractive for applications.

[0063] FIG. 7 illustrates Laser-Induced Changes are Reversable, demonstrating Write-read-erase-reuse Capability. PL intensity and PL peak position evolution as a function of air vs. vacuum (0.226 Torr) environment, while the 2D heterostructure is exposed to a low-power (70 μW) 532 nm laser. The PL intensity and PL peak position can be tuned over a large range with high precision. Fluorescence images and optical images corresponding to the data, showing changes to the fluorescence and optical color due to laser exposure.

[0064] After 1.sup.st vacuum exposure showing no detectable change. After 1.sup.st air exposure, showing the pixel turning “on”. After 2.sup.nd vacuum exposure, showing the pixel turning “off”. After the 2.sup.nd air exposure, showing the pixel turning back “on”. No color changed induced by the laser. Color change induced. Color change remains. Together these results show write-read-erase-reuse capability. The data was collected using a 50× ultralong objective due to setup constraints. A smaller laser spot and pixel size can be achieved using a 100× objective.

[0065] FIG. 8 illustrates Hysteresis behavior described by Fick's Law of Diffusion well. PL Intensity and PL peak position from 2.sup.nd vacuum exposure and 2.sup.nd air exposure shown in FIG. 5. The multistate and hysteresis behavior suggests the material is reusable and has applications for neurocomputing technology. The close fit with Fick's Law of Diffusion suggests that a gas is diffusing into and out of the material. As discussed later, oxygen is likely diffusing into and out of the material.

[0066] FIG. 9 illustrates Oxygen required to induce changes, demonstrating oxygen sensing applications. PL intensity and PL peak position as a function of vacuum (0.226T) vs. 99.9% oxygen (0.226T) environment, while the 2D heterostructure is exposed to a low-power (70 μW) 532 nm laser. When exposed to oxygen, changes are induced, suggesting oxygen is required for the primary mechanism. Changes are not induced when exposed to nitrogen while a laser is applied.

[0067] FIG. 10 illustrates changes are stable for long term with no detectable degradation. 2D Heterostructures were written with a laser, and kept in a nitrogen environment at room temperature. No detectable changes are observed, suggesting the laser-induced changes are robust.

[0068] FIG. 11 illustrates a demonstration of writing continuous (non-discrete) patterns.

[0069] FIG. 12 illustrates representative Raman Spectra of an as-grown Bi.sub.2Se.sub.3/WS.sub.2 2D Heterostructure.

[0070] FIG. 13 illustrates Raman Signature evolves with initial laser-oxygen exposure. RLRR measurements correlated to laser-oxygen exposure measurements in FIG. 4.

[0071] FIG. 14 illustrates No detectable effect of laser-vacuum exposure on the Raman modes. Although laser exposure in vacuum reverses the changes to the PL intensity and peak position, no changes to the Raman modes were detected. The above data is RLRR taken concurrent with the atmosphere cycling shown in FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

[0072] This disclosure teaches methods and devices for write-read-erase-reuse pixels with tunable circular polarization, emission energy (wavelength), and intensity. The pixels can be written with submicron features (814 nm), and the data can be read using fluorescence imaging, enabling superdense optical data storage and rapid read capability.

[0073] Optical communications and data storage are a promising avenue to overcome bandwidth and power density limitations through electrical connections.

[0074] Circular polarization is tunable using a low-power laser at room temperature, suggesting simple and low-cost integration without the need for external temperature control.

[0075] Material is nanoscale (˜2-5 nm tall), suggesting it integrates well with next-generation nano-technology.

[0076] Material is grown using a two-step chemical vapor deposition (CVD) process, suggesting fabrication is scalable and low-cost.

[0077] We demonstrated write-read-erase-reuse capability.

[0078] We demonstrated laser writing with submicron (814 nm) feature resolution.

[0079] Laser-written patterns are stable for more than several months at room temperature.

[0080] We demonstrated that the DoCP is reversible, along with the PL intensity and peak position, and that it can be reliably tuned within a range. DoCP was measured as the atmosphere was switched between air vs. vacuum.

[0081] We also demonstrated the following secondary applications and technology:

[0082] Highly-tunable photoluminescence intensity across a large (×160 factor) range.

[0083] Highly-tunable photoluminescence peak position across a large (˜38 meV) range.

[0084] Oxygen sensor applications are demonstrated.

[0085] Oxygen storage and release in a 2D material are mostly demonstrated, suggesting lab-on-a-chip applications.

EXAMPLE 1

[0086] Monolayer transition metal dichalcogenides (TMDs) are synthesized at ambient pressure in 2-inch diameter quartz tube furnaces on SiO.sub.2/Si substrates (275 nm thickness of SiO.sub.2). The procedure to grow monolayer WS.sub.2 follow similar steps, as outlined below, but are performed in separate furnaces to prevent cross-contamination.

EXAMPLE 2

[0087] Prior to use, all SiO.sub.2/Si substrates are cleaned in acetone, IPA, and Piranha etch (H.sub.2SO.sub.4+H.sub.2O.sub.2) then thoroughly rinsed in DI water. At the center of the furnace is positioned a quartz boat containing ˜1 g of WO.sub.3 powder. Two SiO.sub.2/Si wafers are positioned face-down, directly above the oxide precursor. A separate quartz boat containing sulfur powder is placed upstream, outside the furnace-heating zone, for the synthesis of WS.sub.2. The upstream SiO.sub.2/Si wafer contains perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS) seeding molecules, while the downstream substrate is untreated. The hexagonal PTAS molecules are carried downstream to the untreated substrate and promote lateral growth of the monolayer WS.sub.2. Pure argon (65 sccm) is used as the furnace heats to the target temperature. Upon reaching the target temperature of 825° C., 10 sccm H.sub.2 is added to the Ar flow and maintained throughout the 10 minute soak and subsequent cooling to room temperature.

EXAMPLE 3

[0088] Bi.sub.2Se.sub.3 was grown on top of the TMDs using chemical vapor deposition (CVD) in a two-zone furnace with a 2″ quartz tube. High-purity Bi.sub.2Se.sub.3 flakes are ground using a mortar and pestle into a fine dust. The powdered Bi.sub.2Se.sub.3 is placed in a ceramic boat and inserted into the furnace's quartz tube, and pushed into the center of the furnace's first zone. The monolayer TMD, which is on an SiO.sub.2 substrate, is placed downstream of the Bi.sub.2Se.sub.3 into the center of the furnace's second zone. The furnace is pumped down to ˜20 mTorr. An argon (Ar) carrier gas is flown into the furnace at 80 sccm. The Bi.sub.2Se.sub.3 is heated to 520° C., and the WS.sub.2 are heated to 210° C. The ramp rate is ˜55° C./min, and the total growth is 27 min.

EXAMPLE 4

[0089] FIG. 1 shows a schematic of the Bi.sub.2Se.sub.3/WS.sub.2 2D heterostructure as well as characterization of the system. Monolayer WS.sub.2 is grown on a SiO.sub.2/Si wafer using chemical vapor deposition (CVD), and then 1-3 layers of Bi.sub.2Se.sub.3 is grown on the monolayer WS.sub.2 using CVD. CVD is a highly scalable and a comparatively low-cost growth method, making the material attractive for commercialization. FIG. 1 is a illustration of the material. FIG. 1 is an optical image of the material, where the triangular design suggests the WS.sub.2 grows crystalline. FIG. 1 is an atomic force microscope (AFM) scan of a representative Bi.sub.2Se.sub.3/WS.sub.2 2D heterostructure showing near complete coverage of Bi.sub.2Se.sub.3 on WS.sub.2. A majority of the sample has bilayer Bi.sub.2Se.sub.3 with islands of trilayer Bi.sub.2Se.sub.3 and gaps of monolayer Bi.sub.2Se.sub.3.

EXAMPLE 5

[0090] FIG. 2 shows s transmission electron microscope (TEM) image and diffraction measurement of a Bi.sub.2Se.sub.3-WS.sub.2 2D heterostructure. Monolayer Bi.sub.2Se.sub.3 flakes several microns in size were grown on monolayer WS.sub.2. The well-formed spots in the diffraction image suggest both Bi.sub.2Se.sub.3 and WS.sub.2 have long-range crystallinity. Additionally, the Bi.sub.2Se.sub.3 crystals appear to grow at a 0° twist angle, suggesting this is the most stable configuration, and the interlayer interaction modulates the growth.

EXAMPLE 6

[0091] Another embodiment of the invention is laser-written (814 nm) submicron pixels with tunable circular polarization and write-read-erase-reuse capability on a two-dimensional (2D) nano material (i.e., monolayer WS.sub.2 with 1-3 layers Bi.sub.2Se.sub.3 grown on top) at room temperature. Secondary modes include: tunable photoluminescence (PL) intensity and peak position (e.g., emission color/wavelength) for superdense multidimensional optical data storage, as well as oxygen sensing and storage applications.

EXAMPLE 7

[0092] FIG. 3 demonstrates how laser exposure in an oxygen-present environment (e.g., air) can be used to write or pattern the 2D heterostructure. FIG. 3 is an illustration showing the setup. FIG. 3 is an optical image after patterning the letter “N” into the 2D heterostructure using laser exposure in air. Laser exposure in an oxygen-present atmosphere induces a color change from purple to a lighter variant. FIG. 3 is a fluorescence image of the same 2D heterostructure from FIG. 3, demonstrating submicron (814 nm) feature resolution. Large differences in brightness are due primarily to different exposure times. FIG. 3 representative PL spectra from an as-grown 2D heterostructure and after various exposure times in air, showing the large increase in PL intensity and peak position shifts. The PL peak position evolution is nonlinear, initially shifting to higher energies, before reversing direction and shifting to lower energies.

[0093] The above examples are merely illustrative of several possible embodiments of various aspects of the present disclosure, wherein equivalent alterations and/or modifications will occur to others skilled in the art upon reading and understanding this specification and the annexed drawings. In addition, although a particular feature of the disclosure may have been illustrated and/or described with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Also, to the extent that the terms “including”, “includes”, “having”, “has”, “with”, or variants thereof are used in the detailed description and/or in the claims, such terms are intended to be inclusive in a manner similar to the term “comprising”.