System and method based on multi-source deposition for fabricating perovskite film

Abstract

A system and method for fabricating a perovskite film is provided, the system including a substrate stage configured to rotate around its central axis at a rotation speed, a first set of evaporation units, each coupled to the side section or the bottom section of the chamber, a second set of evaporation units coupled to the bottom section, and a shield defining two or more zones having respective horizontal cross-sectional areas, which are open and facing the substrate, designated for the two or more evaporation units in the second set. The resultant perovskite film includes multiple unit layers, wherein each unit layer is formed by one rotation of the substrate stage, and the composition and thickness of the unit layer are controlled by adjusting at least the evaporation rates, the rotation speed and the horizontal cross-sectional areas.

1 - 34 . (canceled) 
     
     
         35 . A system for fabricating a perovskite film, wherein source materials include an organic halide compound AX and a metal halide compound BX 2 , wherein halogen X in the AX and halogen X in the BX 2  are the same or different, the system comprising:
 a chamber having a closed hollow structure that has a side section along a vertical direction and top and bottom sections along a horizontal direction;   a substrate stage coupled to the top section of the chamber and configured to have a stage surface facing vertically downward for a substrate to be placed and to rotate around a central axis at a rotation speed;   a first set of evaporation units comprising one or more evaporation units, each coupled to the side section or to the bottom section of the chamber, for generating vapors of one or more first source materials with one or more first evaporation rates, respectively, wherein at least one of the one or more first source materials is the AX;   a second set of evaporation units comprising two or more evaporation units coupled to the bottom section of the chamber for generating vapors of two or more second source materials with two or more second evaporation rates, respectively, wherein at least one of the two or more second source materials is the BX 2 ; and   a shield for separating two or more evaporation units coupled to the bottom section of the chamber, defining two or more zones designated for the two or more evaporation units coupled to the bottom section, respectively, wherein the zone designated for each of the two or more evaporation units in the second set is configured to have a horizontal cross-sectional area that is open and facing the substrate surface,   wherein the first set of evaporation units, the second set of evaporation units and the shield are configured to enable deposition of each of the two or more second source materials to be substantially directional by vertical line-of-sight transfer, and deposition of each of the one or more first source materials to be substantially less directional by circulating the vapor of the first source material in the chamber.   
     
     
         36 . The system of  claim 35 , wherein
 at least the one or more first evaporation rates, the two or more second evaporation rates, the rotation speed and the two or more horizontal cross-sectional areas are adjusted to control composition and thickness of a unit layer to fabricate the perovskite film comprising a plurality of unit layers, wherein each unit layer is formed by one rotation of the substrate stage.   
     
     
         37 . The system of  claim 35 , wherein
 at least one of the one or more evaporation units in the first set is coupled to the side section of the chamber.   
     
     
         38 . The system of  claim 35 , wherein
 at least one of the one or more evaporation units in the first set is coupled to the bottom section of the chamber, and   the shield is configured to include a top shield portion above the at least one of the one or more evaporation units in the first set to promote the circulation of the vapor of the first source material therefrom by reducing the vapor directly hitting the substrate.   
     
     
         39 . The system of  claim 35 , wherein
 at least one of the one or more evaporation units in the first set is coupled to the bottom section of the chamber, and   an opening portion of the shield for the at least one of the one or more evaporation units in the first set is oriented to face away from the substrate surface to promote the circulation of the vapor of the first source material therefrom by reducing the vapor directly hitting the substrate.   
     
     
         40 . The system of  claim 35 , wherein
 at least one of the one or more evaporation units in the first set is coupled to the bottom section of the chamber away from the two or more evaporation units in the second set to avoid an overlap between a horizontal cross-sectional area of the substrate surface and that of the at least one of the one or more evaporation units in the first set.   
     
     
         41 . The system of  claim 36 , wherein
 the two or more second source materials are two or more types of the BX 2 , respectively,   wherein at least the one or more first evaporation rates, the two or more second evaporation rates, the rotation speed and the two or more horizontal cross-sectional areas are adjusted to form two or more sub-layers in the unit layer, the two or more sub-layers including at least elements of the two or more types of the BX 2 , respectively.   
     
     
         42 . The system of  claim 36 , wherein
 one of the two or more second source materials is a dopant material,   wherein at least the one or more first evaporation rates, the two or more second evaporation rates, the rotation speed and the two or more horizontal cross-sectional areas are adjusted to form the unit layer with a predetermined dopant concentration.   
     
     
         43 . The system of  claim 36 , wherein
 one of the one or more first source materials is a dopant material,   wherein at least the one or more first evaporation rates, the two or more second evaporation rates, the rotation speed and the two or more horizontal cross-sectional areas are adjusted to form the unit layer with a predetermined dopant concentration.   
     
     
         44 . A method for fabricating a perovskite film by using a system of  claim 35 , the method comprising:
 controlling a temperature of the substrate stage for providing uniform cooling or heating to the substrate;   rotating the substrate stage at the rotation speed;   controlling temperatures associated with the one or more evaporation units in the first set and the two or more evaporation units in the second set to adjust the one or more first evaporation rates and the two or more second evaporation rates, respectively;   monitoring a film thickness in situ; and   interrupting the deposition when the film thickness reaches a predetermined thickness.   
     
     
         45 . The method of  claim 44 , further comprising:
 predetermining at least the one or more first evaporation rates, the two or more second evaporation rates, the rotation speed and the two or more horizontal cross-sectional areas to control composition and thickness of a unit layer to fabricate the perovskite film comprising a plurality of unit layers, wherein each unit layer is formed by one rotation of the substrate stage.   
     
     
         46 . The method of  claim 44 , wherein the system further comprises a shutter provided below the substrate stage, and a plurality of evaporation shutters provided for the one or more evaporation units in the first set and for the two or more evaporation units in the second set, respectively, the method further comprising:
 closing the shutter to cover the substrate stage before the deposition;   opening the shutter to expose the substrate stage to start the deposition; and   adjusting the plurality of evaporation shutters to control flows of the vapors of the first and second source materials, respectively,   wherein the interrupting the deposition comprises closing the shutter.   
     
     
         47 . A perovskite film fabricated by using the method of  claim 44 , wherein a root mean square roughness per atomic force microscopy (AFM) is less than 40 nm without annealing. 
     
     
         48 . The system of  claim 35 , wherein the A is an organic element selected from a group consisting of methylammonium (MA) and formamidinium (FA), the B is a metal element selected from a group consisting of Pb and Sn, and the X is a halogen element selected from a group consisting of Cl, I and Br.