Thermal evaporation method for preparation of near-stoichiometric CdS film with quantum dot as precursor

Abstract

The invention discloses a thermal evaporation method for preparation of a near-stoichiometric CdS film with a quantum dot as the precursor. The method includes: putting a cleaned substrate on a sample rack (Emitech, K950X) of a thermal evaporimeter vacuum chamber, putting 0.1-0.3g of the precursor with an appropriate size into a W basket and closing the chamber, under room temperature, conducting vacuum pumping on the chamber to 1.0*10<3>-1.0*10<5>mbar, adjusting the current passing through the W basket to control the evaporation rate, firstly slowly increasing the current from 0A to 6-10A to wait until the W basket turns red, then further increasing the current to 13-20A and keeping the state for 5-10s, and finally, reducing the current to 0A to complete the whole evaporation process. The method provided by the invention adopts a single-source thermal evaporation technique, avoids the problem of complex control of each evaporation source in multi-source thermal evaporation technique, and adopts CdS QDS rich in Cd element as the precursor. The preparation method is room temperature co-precipitation method, is easy to operate and has high yield.

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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