A METHOD FOR FORMING A FILM OF A PEROVSKIT-LIKE MATERIAL

Abstract

To improve the quality of semiconductor films, to reduce the culling of finished products, the parameters of which do not meet the established requirements in the method of forming a semiconductor film of a perovskite-like material, a layer of a perovskite-like material or a precursor of a perovskite-like material of the predefined thickness is deposited on the substrate, followed by halogen layer until liquefaction of the layer, then the halogen is gradually removed from the substrate until it is completely removed, ensuring the gradual crystallization of the perovskite-like material on a substrate to form perovskite-like material grains larger than perovskite-like material grains of the original film.

Claims

1. A method of forming a semiconductor film of a perovskite-like material, wherein a layer of perovskite-like material of predetermined thickness is deposited on a substrate and exposed to halogen until partial liquefaction of the layer, and then the halogen is gradually removed from the substrate, ensuring gradual crystallization perovskite-like material on a substrate with the formation of grains of a perovskite-like material of a size larger than size of grains of a perovskite-like material in the initial layer.

2. The method according to claim 1, wherein the layer of the perovskite-like material is made in the form of a precursor of the perovskite-like material, which contains, in addition to the components of the desired perovskite-like material, other chemicals

3. The method according to claim 1, wherein the precursor contains solvent molecules.

4. The method according to claim 1, wherein the semiconductor material layer has a chemical composition of ABX.sub.3, where at least one of the CH.sub.3NH.sub.3.sup.+ or (NH.sub.2).sub.2CH.sup.+ or C(NH.sub.2).sub.3.sup.+ or Cs.sup.+ or Rb.sup.+ cations or their mixture is used as component A, at least one of the elements Pb, Sn, Bi, Cu, Ge, Ca, Sr, Ti or their mixture is used as component B and as a component X is used at least one of halogens Cl.sup.− or Br.sup.− or I.sup.− or their mixture.

5. The method according to claim 1, wherein the film to be treated contains in the elemental composition the components of the ABX.sub.3 compound.

6. The method according to claim 1, wherein the rate of halogen removal from the substrate is regulated.

7. The method according to claim 6, wherein the initial rate of halogen removal from the substrate is chosen to ensure the formation in the layer of crystallization centers with a predetermined number of crystallization centers per unit area of the substrate.

8. The method according to claim 1, wherein the halogen on the substrate is separated from the gas phase

9. The method according to claim 1, wherein substrate is exposed to halogen that is used in the form of pure liquid halogen or in the form of a solution containing halogen.

10. The method according to claim 4, wherein applying halogen from the gas phase, uses a gas mixture containing a vapor of component A.

11. The method according to claim 7, wherein during the processing of the semiconductor film with halogens, the substrate and/or the solution and/or the gas mixture containing halogens is heated

12. The method according to claim 11, wherein the halogen-containing reaction mixture is supplied under pressure

13. The method according to claim 6, wherein the removal of excess halogens and/or reaction products is performed while using temperature treatment (cooling or heating) or purging a semiconductor film by a controlled flow of inert gas or by exposure in a low pressure directly after affection of halogens to the film on a perovskite-like film material.

14. The method according to claim 1, wherein during the formation of the photoelectric layer, the formation of grains ranging in size from 100 nm to 100 μm is provided, and iodine vapor with a partial pressure of 0.000001 atm to 0.99 atm is used to liquefy the layer.

Description

[0021] The possibility of implementing the proposed method in various embodiments with the achievement of the technical result is confirmed by the examples below:

[0022] Example 1: A film of composition CH.sub.3NH.sub.3PbI.sub.3, obtained by deposition from a solution in dimethyl sulfoxide with a thickness of 300 nm, was treated with iodine vapor in a closed glass vessel, at the bottom of which crystalline iodine was placed. The treatment was carried out for 3 minutes at room temperature, after which the initial film was removed from the atmosphere of iodine and examined by scanning electron microscopy. An analysis of micrographs revealed an increase in the average grain size from ˜50 nm to ˜200 nm

[0023] Example 2: analogously to example A (example 1), but the treatment was carried out while maintaining the reaction vessel at T=40° C. for 1 minute. An analysis of micrographs revealed an increase in the average grain size from ˜50 nm to ˜300 nm

[0024] Example 3: analogously to example A, the process was carried out while maintaining the temperature of the substrate at T=60° C., which was treated for 3 minutes with a gas stream blown through crystalline iodine kept at T=40° C. An analysis of the micrographs of the film revealed an increase in the average grain size from ˜50 nm to ˜400 nm.

[0025] Example 4: analogously to example A, but the films of composition Cs.sub.0.05 (MA.sub.0.17FA.sub.0.83) PbI.sub.3 were subjected to treatment at T=40° C. for 3 minutes. An analysis of micrographs revealed an increase in the average grain size from ˜50 nm to ˜200 nm, an analysis of the phase composition of the film showed that the ratio of cations A in it did not change compared with the initial one.

[0026] Despite the fact that the analytical dependence of grain sizes and their properties on the halogen concentration in the initial solution and the halogen removal rate has not been found, the required parameters can be determined empirically.

[0027] In addition, it is revealed that a significant, 3 times or more, decrease in the halogen removal rate after the formation of the required number of crystallization centers per unit volume of the layer or per unit surface area of the substrate, ensures the formation of grains of a stable size in a given amount.