Preparation method for copper indium gallium diselenide thin film

Abstract

The invention relates to a preparation method for a copper indium gallium diselenide thin film. The preparation method for the copper indium gallium diselenide thin film comprises the steps of 1, co-evaporating gallium and indium in a selenium atmosphere to enable the selenium, the gallium and the indium to be deposited on a substrate; 2, heating the substrate, and evaporating copper in the selenium atmosphere to enable the selenium and the copper to be deposited on the substrate; 3, preserving the temperature of the substrate, and co-evaporating the gallium and the indium in the selenium atmosphere to form the copper indium gallium diselenide thin film. A ratio of the co-evaporating time in the step 1 to the co-evaporating time in the step 3 is (5:1)-(7:1). By virtue of rising of the evaporating temperature of the hot gallium and the indium, acceleration of thin film deposition and setting of the ratio relation between the evaporation amount in the step 1 and the evaporation amount in the step 3, the much indium can enter the thin film, and the gallium content of the surface of the thin film can be increased; therefore, the gradient distribution of all the elements can be obviously improved, defects on the surface of the copper indium gallium diselenide thin film can be reduced, the quality of the copper indium gallium diselenide thin film can be improved, and the energy consumption is reduced.

Description

technical field [0001] The invention relates to the technical field of photovoltaic device preparation, in particular to a method for preparing a copper indium gallium selenide thin film. Background technique [0002] In the laboratory of scientists, the co-evaporation process is currently the most widely used and efficient method for preparing copper indium gallium selenide (CIGS) thin film solar cells. The world record of 20.4% photoelectric conversion rate is established by the Swiss Federal Materials Testing and Development achieved by the co-evaporation method. The basic principle of the co-evaporation method is to place four evaporation source targets of copper (Cu), indium (In), gallium (Ga), and selenium (Se) in a vacuum chamber. When the target is heated to the surface with target molecules When detached from the evaporation source, deposition will occur on the substrate, and the target molecules on the substrate will react with each other, finally forming a CIGS c...

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Problems solved by technology

Therefore, if the deposition rate is simply increased, due to the short film growth time, the grains cannot be fully grown, the grain size is small, and the grain boundaries increase; and the random orientation (112) increases, and the surface roughness and defect states increase; The distribution also forms a steep gradient due to insufficient diffusion, and the quality of the prepared CIGS thin film is poor, which eventually leads to a significant decline in the performance of the entire device.

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