Two-dimensional semiconductor device, optoelectronic unit and method for making the two-dimensional semiconductor device

Abstract

Disclosures of the present invention mainly describe a two-dimensional semiconductor device (TDSD), comprising: a two-dimensional semiconductor material (TDSM) layer, a superacid action layer and a superacid solution. The TDSM layer is made of a transition-metal dichalcogenide, and the superacid action layer is formed on the TDSM layer. Particularly, an oxide material is adopted for making the superacid action layer, such that the superacid solution is subsequently applied to the superacid action layer so as to make the superacid solution gets into the superacid action layer by diffusion effect. Experimental data have proved that, letting the superacid solution diffuse into the superacid action layer can not only apply a chemical treatment to the TDSM layer, but also make the TDSD have a luminosity enhancement. Particularly, the luminosity enhancement would not be reduced even if the TDSD contacts with water and/or organic solution during other subsequent manufacturing processes.

Claims

1. An optoelectronic unit, being a microresonator, and comprising: a bottom distributed Bragg reflector mirror; a two-dimensional (2D) semiconductor device, being disposed on the bottom distributed Bragg reflector mirror for being used as a gain medium so as to make a lighting device integrated with the optoelectronic unit has a luminosity enhancement, and comprising: a two-dimensional (2D) semiconductor material layer; a superacid action layer, being formed on the 2D semiconductor material layer, and having a thickness in a range between 5 nm and 100 nm, wherein the superacid action layer is made of an oxide material selected from a group consisting of SiO.sub.2, HfO.sub.2, TiO.sub.2, and Al.sub.2O.sub.3; and a superacid solution, being applied to the superacid action layer, so as to get into the superacid action layer by diffusion effect; and a top distributed Bragg reflector mirror, being disposed on the 2D semiconductor device.

2. The optoelectronic unit of claim 1, further comprising a buffer layer BF disposed between the bottom distributed Bragg reflector mirror and the 2D semiconductor material layer, so as to make the buffer layer and the 2D semiconductor device have a thickness greater than 200 nm.

3. The optoelectronic unit of claim 1, wherein the 2D semiconductor material layer is made of a material selected from the group consisting of MoS.sub.2, WS.sub.2 and WSe.sub.2.

4. The optoelectronic unit of claim 1, the superacid solution comprises a superacid solute and a solvent.

5. The optoelectronic unit of claim 4, wherein the superacid solute is a solute selected from the group consisting of bis(trifluoromethane)sulfonamide (TFSI), trifluoromethanesulfonic acid, fluorosulfonic acid, fluoroantimonic acid, magic acid, carboronic acid, and a combination of two or more the foregoing solute.

6. The optoelectronic unit of claim 4, wherein the solvent is selected from the group consisting of dichloromethane, 1,2-dichloroethylene, 1,2-dichloroethane, chloroform, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene 1,1,2,2-tetrachloroethane, tetrachloroethylene, carbon tetrachloride, and chlorobenzene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention as well as a preferred mode of use and advantages thereof will be best understood by referring to the following detailed description of an illustrative embodiment in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 shows a schematic stereo view of a monolayer TDMCs with superacid and encapsulating material;

(3) FIG. 2 shows a schematic stereo view of a two-dimensional (2D) semiconductor device according to the present invention;

(4) FIG. 3 shows a flowchart diagram of a method for making the 2D semiconductor device according to the present invention;

(5) FIG. 4 shows schematic diagrams for describing a manufacturing flow of the 2D semiconductor device;

(6) FIG. 5 shows a statistical bar graph of enhancement factor versus count number;

(7) FIG. 6 shows a statistical bar graph of enhancement factor versus count number; and

(8) FIG. 7A and FIG. 7B show schematic diagrams for describing an optoelectronic unit having the 2D semiconductor device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) To more clearly describe a two-dimensional (2D) semiconductor device, a method for making the 2D semiconductor device, and an optoelectronic unit comprising the 2D semiconductor device disclosed by the present invention, embodiments of the present invention will be described in detail with reference to the attached drawings hereinafter.

(10) Structure of Two-Dimensional (2D) Semiconductor Device

(11) With reference to FIG. 2, there is a schematic stereo view of a two-dimensional (2D) semiconductor device according to the present invention. As FIG. 2 shows, the 2D semiconductor device 1 of the present invention comprises a two-dimensional (2D) semiconductor material layer 11, a superacid action layer 12 and a superacid solution 13. The 2D semiconductor material layer 11 is made of a transition-metal dichalcogenide (TMDC) having a chemical formula of MX.sub.2, wherein M is a transition metal of the IVB-VIB group in the Periodic Table. On the other hand, X is a chalcogen (chalcophile element) coming from the VIA group in the Periodic Table, such as S, Se and Te. A monolayer 2D TMDC has a layer structure of X—M—X, wherein links between respective X atoms and respective M atoms are achieved by covalent bonds in the layer structure. Moreover, a multi-layered 2D TMDC can also be formed by connecting two or more the monolayer 2D TMDCs using van der Waals forces. In the present invention, MoS.sub.2, WS.sub.2 and WSe.sub.2 are adopted for the manufacture of the 2D semiconductor material layer 11 because their band gap is found to be adjustable in a range between 0.8 eV and 2.0 eV.

(12) On the other hand, the a superacid action layer 12 is formed on the 2D semiconductor material layer 11, and has a thickness in a range from 5 nm to 100 nm. According to the particular design of the present invention, the superacid solution 13 is applied to the superacid action layer 12, so as to get into the superacid action layer 12 by diffusion effect. It is worth emphasizing that, the processing way for applying the superacid solution 13 to the superacid action layer 12 should not be limited. For example, the superacid solution 13 can be applied to the superacid action layer 12 by coating, spraying or inkjet printing process. In addition, it can also let the superacid action layer 12 be soaked in the superacid solution 13 for making the superacid solution 13 diffuse into the superacid action layer 12.

(13) In the present invention, the superacid action layer 12 is made of an oxide, such as SiO.sub.2, HfO.sub.2, TiO.sub.2, and Al.sub.2O.sub.3. On the other hand, the superacid solution 13 comprises a superacid solute and a solvent, wherein the superacid solute is a solute selected from the group consisting of bis(trifluoromethane)sulfonamide (TFSI), trifluoromethanesulfonic acid, fluorosulfonic acid, fluoroantimonic acid, magic acid, carboronic acid, and a combination of two or more the foregoing solute. Moreover, the solvent is selected from the group consisting of dichloromethane, 1,2-dichloroethylene, 1,2-dichloroethane, chloroform, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene 1,1,2,2-tetrachloroethane, tetrachloroethylene, carbon tetrachloride, and chlorobenzene.

(14) Method for Making the 2D Semiconductor Device

(15) Please refer to FIG. 3, which shows a flowchart diagram of a method for making the 2D semiconductor device according to the present invention. Moreover, FIG. 4 illustrates schematic diagrams for describing a manufacturing flow of the 2D semiconductor device. As FIG. 3 and FIG. 4 show, step S1 is firstly executed for fabricating the 2D semiconductor device shown as FIG. 3. Herein, it needs to further explain that, the 2D semiconductor material layer 11 is firstly formed on the substrate 10, and is subsequently transferred from the substrate 10 to one surface of a target object, such that the 2D semiconductor material layer 11 is therefore provided. Of course, it is allowed to directly form the 2D semiconductor material layer 11 on the surface of the target object. Si substrate or SiO.sub.2 substrate are commonly used as the substrate 10 for carrying the 2D semiconductor material layer 1. However, these two types of substrates should not form a limitation of the embodiments of the substrate 10. In the present invention, the substrate 10 can be a flexible substrate or a solid substrate, wherein the solid substrate is selected from the group consisting of Gallium arsenide (GaAs) substrate, sapphire (Al.sub.2O.sub.3) substrate, aluminum nitride (AlN) substrate, spinel substrate, and glass substrate. On the other hand, the flexible substrate is made of a polymer material such as polyethylene terephthalate (PET), polycarbonate (PC), polyimide (PI) substrate, or polyethylene (PE).

(16) Subsequently, method flow is proceeded to step S2 for forming a superacid action layer 12 on the 2D semiconductor material layer 11. As diagram (a) of FIG. 4 shows, SiO.sub.2 is adopted for forming a superacid action layer 12 on the 2D semiconductor material layer 11 through atomic layer deposition (ALD). Consequently, method flow is proceeded to step S3 for applying a superacid solution 13 to the superacid action layer 12, such that the superacid solution 13 subsequently gets into the superacid action layer 12 by diffusion effect. From diagrams (b) and (c) of FIG. 4, it is shown that bis(trifluoromethane)sulfonamide (TFSI) is applied to the superacid action layer 12 and subsequently diffuse into the superacid action layer 12.

(17) Experiments

(18) Inventors of the present invention have complete related experiments for proving that letting the superacid solution 13 diffuse into the superacid action layer 12 is helpful for not only applying a chemical treatment to the 2D semiconductor material layer 11 but also make the 2D semiconductor device 1 have a luminosity enhancement. Following Table (1) lists four groups including different testing samples arranged by the inventors, wherein the four groups are respectively control group I, experimental group I, control group II, and experimental group II.

(19) TABLE-US-00001 TABLE 1 Groups Testing samples control group I A 2D semiconductor material layer 11, wherein a superacid solution 13 comprising a superacid solute of TFSI and a solvent of CH.sub.2Cl.sub.2 is applied to the 2D semiconductor material layer 11. experimental A 2D semiconductor device 1 shown as FIG. 2, which group I comprises a 2D semiconductor material layer 11, a superacid action layer 12 and a superacid solution 13, and the superacid solution 13 comprising a superacid solute of TFSI and a solvent of CH.sub.2Cl.sub.2. control group II A 2D semiconductor material layer 11, wherein a superacid solution 13 comprising a superacid solute of TFSI and a solvent of CHCl.sub.3 is applied to the 2D semiconductor material layer 11. experimental A 2D semiconductor device 1 shown as FIG. 2, which group II comprises a 2D semiconductor material layer 11, a superacid action layer 12 and a superacid solution 13, and the superacid solution 13 comprising a superacid solute of TFSI and a solvent of CHCl.sub.3.

(20) FIG. 5 and FIG. 6 shows respective statistical bar graphs of enhancement factor versus count number. The phrase of count number means sample number, and the term of enhancement factor represents a fold of luminosity enhancement of the 2D semiconductor material layer 11. From the experimental data of FIG. 5 and FIG. 6, it can easily find that, the 2D semiconductor device 1 proposed by the present invention exhibit a relatively high luminous gain after being compared to the 2D semiconductor material layer 11 which has been applied a chemical treatment by the TFSI solution (i.e., superacid solution).

(21) Applications of the 2D Semiconductor Device

(22) Apparently, related experimental data have proved that, letting the superacid solution 13 diffuse into the superacid action layer 12 can not only apply a chemical treatment to the 2D semiconductor material layer 11, but also make the 2D semiconductor device 1 have a luminosity enhancement. Moreover, the luminosity enhancement would not be reduced even if the 2D semiconductor device 1 contacts with water and/or organic solution during other subsequent manufacturing processes. In addition, above-descriptions also indicate that the 2D semiconductor material layer 11 formed on the substrate 10 can also be further transferred to one surface of a target object with respect to different application of the 2D semiconductor material layer 11. There are schematic diagrams provided in FIG. 7A and FIG. 7B for describing an optoelectronic unit having the 2D semiconductor device. As diagram (a) in FIG. 7A shows, a bottom distributed Bragg reflector (DBR) mirror BBM is provided a buffer layer BF thereon, and the bottom DBR mirror BBM is supported by a substrate 20. Moreover, from diagrams (b)-(c) in FIG. 7A and diagram (d) in FIG. 7B, it is understood that, a 2D semiconductor device 1 can be subsequently formed on the bottom DBR mirror BBM through the steps S1-S3 introduced above. As diagram (e) of FIG. 7B shows, a top distributed Bragg reflector (DBR) mirror TBM is consequently disposed on the 2D semiconductor device 1 comprising the 2D semiconductor material layer 11, the superacid action layer 12 and the superacid solution 13. Electronic engineers skilled in development and manufacture of optoelectronic devices should know that, the optoelectronic unit comprising the bottom DBR mirror BBM, the 2D semiconductor device 1 and the top DBR mirror TBM is a microresonator.

(23) Therefore, FIG. 7A and FIG. 7B discloses that the 2D semiconductor device 1 of the present invention can be applied in the manufacture of a microresonator, wherein the buffer layer BF and the 2D semiconductor device 1 have a thickness greater than 200 nm. However, it needs to particularly emphasize that, the application of the 2D semiconductor device 1 is not limited in the manufacture of the microresonator. In other practicable applications, the 2D semiconductor device 1 of the present invention can also be applied in an organic light-emitting diode (OLED) for enhancing the luminous efficiency of the OLED. On the other hand, the 2D semiconductor device 1 can also be applied in the manufacture of a light-emitting diode (LED). Moreover, the 2D semiconductor device 1 can also be configured as a gate isolation layer of a tunneling field-effect transistor (TFET). Furthermore, in other practicable applications, the 2D semiconductor device 1 is configured as a light absorbing member so as to be applied in an optoelectronic device selected from the group consisting of photovoltaic device, photodetector, and Q-switched fiber laser.

(24) The above description is made on embodiments of the present invention. However, the embodiments are not intended to limit scope of the present invention, and all equivalent implementations or alterations within the spirit of the present invention still fall within the scope of the present invention.