A thermal evaporation method for preparing near-stoichiometric cds thin films with quantum dots as precursors

Abstract

The invention discloses a thermal evaporation method for preparing near-stoichiometric CdS thin films with quantum dots as precursors. The cleaned substrate was placed on the sample holder of the vacuum chamber of the thermal evaporator (Emitech, K950X). Close the chamber by placing the appropriate size precursor, 0.1‑0.3 g, in the W basket. At room temperature, the chamber was evacuated to a vacuum of 1.0 x 10-3-1.0 x 10-5 mbar, and the evaporation rate was controlled by adjusting the current through the W basket. First, slowly increase the current from 0 A to 6‑10 A, then wait until the W basket turns red. Then, the current was further increased to 13‑20 A and held for 5‑10 s, and finally, the current was reduced to 0 A to complete the entire evaporation process. The invention adopts single-source thermal evaporation technology, which avoids the complex control problem of each evaporation source in multi-component thermal evaporation technology; uses CdS QDS rich in element Cd as the precursor, and the preparation method is a co-precipitation method at room temperature, which is easy to operate and produces The rate is high.

Description

technical field [0001] The invention belongs to the technical field of material chemistry, and in particular relates to a kind of thermal evaporation that uses cadmium (Cd)-rich cadmium sulfide (CdS) quantum dots as precursors and prepares a near-stoichiometric CdS film in situ on a room temperature substrate. method. Background technique [0002] With the increasing shortage of energy, the development and utilization of new energy has become a hot research issue. Solar energy is a clean and inexhaustible new energy source. A solar cell is a device that directly applies solar energy. CdS is a common semiconductor material that has a wide direct bandgap of about 2.4eV. The wide band gap allows most of the visible light to pass through, the photoconductive effect and high electron affinity make CdS a better window layer and transition layer material in optoelectronic devices. [0003] Currently, different techniques are usually used to prepare CdS thin films with good crys...

AI Technical Summary

Problems solved by technology

However, in order to obtain a precursor rich in Cd, the existing method needs to use powdered CdS, and the CdS powder needs to be heated in a hydrogen flow at 800 °C, which increases the complexity of the preparation process.

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