研究目的
Investigating the integration of lead sulfide quantum dots (QDs) with high conductivity material for the applications of QDs based photodetectors, specifically focusing on the development of a broadband photodetector by combining amorphous ZnO and PbS QDs forming a heterojunction structure.
研究成果
The study successfully developed broadband ZnO/PbS QDs heterojunction photodetectors with amorphous ZnO layers of different oxygen vacancy concentrations. The photodetectors showed high performance in terms of responsivity and detectivity, attributed to the superior electron mobility of ZnO layers and the proper energy band alignment facilitated by the upward shift of the Fermi energy level due to oxygen vacancies. This approach offers a simple and scalable method for developing high-performance broadband photodetectors.
研究不足
The response time of the photodetectors is relatively longer compared with conventional semiconductor photodetectors, which could be related to a strong oxygen absorption/desorption process of surface oxygen vacancies for ZnO layers.
1：Experimental Design and Method Selection:
The study involved the fabrication of amorphous ZnO layers by pulsed laser deposition (PLD) and PbS QDs through a chemical synthesis method. The heterojunction photodetectors were then fabricated by combining these materials.
2：Sample Selection and Data Sources:
Amorphous ZnO layers were grown at different oxygen background pressures (5, 50, 200, and 500 mtorr) to study the effect of oxygen vacancy concentration on the photodetector's performance.
3：List of Experimental Equipment and Materials:
PLD instrument, KrF excimer pulsed laser source, ZnO target, PbS QDs synthesized from PbI2, ODE, OA, and TMS.
4：Experimental Procedures and Operational Workflow:
The ZnO layers were deposited by PLD at room temperature. PbS QDs were synthesized and then spin-coated onto the ZnO layers to form the heterojunction. The devices were characterized for their photodetection performance under 640 nm and 1310 nm illumination.
5：Data Analysis Methods:
The performance of the photodetectors was evaluated based on responsivity (R) and detectivity (D*), calculated from the photocurrent and dark current measurements.
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