EP-4741924-A1 - ASSEMBLY AND METHOD FOR LOCALIZED APPLICATION OF MOLECULES TO A CARRIER

EP4741924A1EP 4741924 A1EP4741924 A1EP 4741924A1EP-4741924-A1

Abstract

The invention relates, among other things, to a method for the localized application of molecules (M) to a support (20), in which a two-dimensional monolayer gas layer (MGS) containing the molecules (M) is formed on the support (20) under vacuum conditions, in which the molecules (M) belonging to the two-dimensional monolayer gas layer (MGS) can move parallel to the surface (21) of the support (20), and by applying an electrical voltage (U) between the support (20) and a needle tip (12) located directly above the support (20) and interacting with the two-dimensional monolayer gas layer (MGS), the molecules (M) of the two-dimensional monolayer gas layer (MGS) located near the needle tip (12) are selectively and permanently localized on the support (20).

Inventors

FRANZ, MARTIN
KUBICKI, Milan
SCHMIDT, DOMINIK

Assignees

Technische Universität Berlin

Dates

Publication Date: 20260513
Application Date: 20241112

Claims (14)

Method for the localized application of molecules (M) onto a support (20), wherein Under vacuum conditions, a two-dimensional monolayer gas layer (MGS) containing the molecules (M) is formed on the support (20), in which the molecules (M) belonging to the two-dimensional monolayer gas layer (MGS) can move parallel to the surface (21) of the support (20), and By applying an electrical voltage (U) between the support (20) and a needle tip (12) located directly above the support (20) and interacting with the two-dimensional monolayer gas layer (MGS), the molecules (M) of the two-dimensional monolayer gas layer (MGS) located near the needle tip (12) can be permanently localized on the support (20).
Method according to claim 1, characterized by the fact that A pattern writing process is carried out in which a pattern with localized molecules (M) is written on the carrier (20), with the polarity of the voltage (U) between carrier (20) and needle tip (12) being inverted during the pattern writing process.
Method according to one of the preceding claims, characterized by the fact that A pattern writing process is carried out in which a pattern with at least two writing sections separated from each other by a separating section is written with localized molecules by guiding the needle tip (12) with a first voltage polarity over the support in the writing sections and in the separating area between the During writing sections, the needle tip (12) is guided over the carrier with a second voltage polarity.
Method according to one of the preceding claims, characterized by the fact that two or more pattern writing processes are carried out, wherein in a first pattern writing process a first molecular monolayer pattern with at least one writing section is written with a first molecule type, and in a second or subsequent pattern writing process a second or subsequent molecular monolayer pattern with at least one writing section is written with a second molecule type or further molecule types, wherein the writing section(s) of the first molecular monolayer pattern are non-overlapping with the writing section(s) of the further molecular monolayer patterns.
Method according to one of the preceding claims, characterized by the fact that The voltage (U) between carrier (20) and needle tip (12) is a positive voltage (U) for the first voltage polarity, where the electrical potential at the carrier (20) is higher than the electrical potential at the needle tip (12), and a negative voltage (U) for the second voltage polarity, where the electrical potential at the carrier (20) is lower than the electrical potential at the needle tip (12).
Method according to one of the preceding claims, characterized by the fact that The voltage (U) between carrier (20) and needle tip (12) is between 2 and 5 volts when writing the writing sections.
Method according to one of the preceding claims, characterized by the fact that the molecules (M) couple with the support (20) to form the two-dimensional monolayer gas layer (MGS) and the two-dimensional monolayer gas layer (MGS) is held on the surface (21) of the support (20) by a holding force caused by the coupled molecules (M), wherein each of the molecules (M) belonging to the two-dimensional monolayer gas layer (MGS) is at any given time forcefully coupled to at least one support atom on the surface (21) of the support (20).
Method according to one of the preceding claims, characterized by the fact that the molecules (M) have a ring structure, all mobile molecules (M) belonging to the two-dimensional monolayer gas layer (MGS) are oriented such that the ring surface of their ring structure lies parallel to the surface (21) of the support (20) and the plane of motion of the monolayer gas layer (MGS), and By applying the electrical voltage (U) between the support (20) and the needle tip (12), the ring structure of the molecules (M) located in the region of the needle tip (12) is rotated out of the plane of the monolayer gas layer (MGS) and thereby immobilized and fixed on the support (20).
Method according to one of the preceding claims, characterized by the fact that the molecules (M) are provided by heating a base material (BM) containing the molecules (M), wherein the heating of the base material (BM) takes place in an effusion chamber (17) takes place during an initial temporal process phase and is completed upon completion of the first process phase, and wherein during this first process phase in the effusion chamber (17) a three-dimensional gas atmosphere containing the vaporized molecules (M) is generated, from which all or at least some of the molecules (M) of the gas atmosphere are deposited on the support (20) forming the monolayer gas layer (MGS), After completion of the first process phase, the carrier (20) together with the monolayer gas layer (MGS) located on it is transferred in a subsequent second process phase from the effusion chamber (17) to an adjacent process chamber (16) also under vacuum conditions, in which the needle tip (12) is located, and the local fixation of the molecules (M) of the monolayer gas layer (MGS) is carried out in the adjacent process chamber (16), and In the second process phase, by applying the electrical voltage (U) between the support (20) and the needle tip (12) in the adjacent process space (16), the molecules (M) of the two-dimensional monolayer gas layer (MGS) located near the needle tip (12) are permanently localized on the support (20).
Method according to any one of the preceding claims 1 to 8, characterized by the fact that the local fixation of the molecules (M) of the monolayer gas layer (MGS) is carried out in the same process chamber (16) in which the molecules (M) in the form of the monolayer gas layer (MGS) were deposited on the support (20), wherein, during the heating of the base material (BM) in the process chamber (16), a three-dimensional gas atmosphere containing the vaporized molecules (M) is generated, from which all or at least some of the molecules (M) of the gas atmosphere are deposited on the support (20) to form the monolayer gas layer (MGS), and wherein, during or after heating, the molecules (M) of the two-dimensional monolayer gas layer (MGS) located near the needle tip (12) are permanently localized on the support (20) by applying the electrical voltage (U) between the support (20) and the needle tip (12).
Method according to one of the preceding claims, characterized by the fact that the needle tip (12) that interacts with the two-dimensional monolayer gas layer (MGS) is a component of a scanning tunneling microscope.
Method according to one of the preceding claims, characterized in that the molecules (M) are N-heterocyclic carbene molecules.
Arrangement for depositing molecules (M) onto a support (20), with an effusion cell (11) for heating a base material (BM) containing the molecules (M) under vacuum conditions and forming a two-dimensional monolayer gas layer (MGS) containing the molecules (M) on the support (20), in which the molecules (M) belonging to the two-dimensional monolayer gas layer (MGS) can move parallel to the surface (21) of the support (20), a needle tip (12) located directly above the support (20) and interacting with the two-dimensional monolayer gas layer (MGS), a voltage source (14) for applying an electrical voltage (U) between the carrier (20) and the needle tip (12), a needle adjustment device (13) and a control device (15) designed to control a pattern writing process by controlling the needle adjustment device (13) and the voltage source (14) and locally generating a writing voltage that leads to the targeted permanent localization of the molecules (M) of the two-dimensional monolayer gas layer (MGS) located near the needle tip (12) on the support (20).
Arrangement according to claim 13, characterized by the fact that the effusion cell (11) and the needle tip (12) are arranged within the same process chamber (16) of a scanning tunneling or atomic force microscope or the effusion cell (11) is arranged in an effusion chamber (17) next to a process chamber (16) of a scanning tunneling or atomic force microscope, wherein the support (20) coated with the two-dimensional monolayer gas layer (MGS) can be transferred under vacuum conditions from the effusion chamber (17) to the process chamber (16) containing the needle tip (12).

Description

The invention relates to arrangements and methods for the localized application of molecules to a support. Several methods are already known that utilize scanning probe microscopy techniques to selectively fabricate nanostructures on surfaces. These can be summarized under the term scanning probe lithography ( SPL). Different physical and chemical effects are used to locally modify the structure of the sample surface beneath a spatially positioned tip. Examples include thermal or thermochemical SPL, where a heated tip is used to structure the surface, and oxidation SPL, where the formation of a water bridge between the tip and the sample leads to local oxidation of the surface. The various methods are described, for example, in the articles listed in the references below [1] and [2]. The invention is based on the objective of providing a method by which a structured molecular monolayer layer can be produced with minimal effort. This problem is solved according to the invention by a method with the features according to claim 1. Advantageous embodiments of the method according to the invention are specified in the dependent claims. According to the invention, a method for the localized application of molecules to a support is provided, in which a two-dimensional monolayer gas layer containing the molecules is formed on the support under vacuum conditions, in which the molecules belonging to the two-dimensional monolayer gas layer can move parallel to the surface of the support, and by applying an electrical voltage between the support and a needle tip located directly above the support and interacting with the two-dimensional monolayer gas layer, the molecules of the two-dimensional monolayer gas layer located near the needle tip are selectively and permanently localized on the support. A significant advantage of the method according to the invention is that by selectively localizing molecules of the monolayer gas layer, patterns can be written in which the areas written with the molecules each consist of only one molecular monolayer. Another significant advantage of the method according to the invention is that it can be carried out with relatively low electrical voltages and thus, compared to other coating methods, without wear or damage, or at least with comparatively low wear or damage. It is advantageous to perform a pattern-writing process in which a pattern or molecular monolayer pattern with localized molecules is written onto the substrate, whereby the polarity of the voltage between the substrate and the tip is inverted during the pattern-writing process. Such a voltage inversion allows, for example, the possibility of recording the pattern while the molecules are not being written or localized. The needle tip is used to scan the substrate for measurement purposes using the inverted voltage, for example, when the method is performed with the needle tip of a scanning tunneling microscope. In the latter case, the tunneling current can be evaluated during the non-writing or non-localization of the molecules for scanning; during the writing process, the tunneling current is generally too noisy for measurement due to the temporally parallel molecular localization. Alternatively, it can also be provided that outside of writing sections, i.e., in separation sections without desired localization of molecules, the needle tip is guided across the substrate with a voltage of zero or another voltage unsuitable for localization. However, the described scanning of the substrate surface in phases where no localization of molecules occurs is generally not possible with a voltage of zero, at least when using a scanning tunneling microscope. In an advantageous embodiment, a pattern writing process is carried out in which a pattern or molecular monolayer pattern with at least one writing section containing localized molecules is written by guiding the needle tip over the support with a first voltage polarity in the writing section and guiding the needle tip over the support outside the writing section with a second voltage polarity that is opposite to the first voltage polarity. A pattern writing process may also be provided, in which a pattern or molecular monolayer pattern with at least two molecules separated from each other by a separating section is created. Writing sections with localized molecules are created by passing the needle tip with the first voltage polarity over the support in the writing sections and passing the needle tip with the second voltage polarity over the support in the separation area between the writing sections. It is particularly advantageous if two or more pattern writing processes are carried out, wherein in a first pattern writing process a first molecular monolayer pattern with at least one writing section is written with a first type of molecule, and in a second pattern writing process a second molecular monolayer pattern with at least one writing section is written with a second