SnSe薄膜热电性能的场效应管调控研究

Thermoelectric material as one kind of environment friendly new energy material can directly convert heat to electricity via utilizing power output produced by the transport of carriers in solids, opening a promising use in waste heat recovery and refrigeration. SnSe is a famous material in thermoelectric field, but the enormous difficulty of tuning the carrier concentration limits the achievement of optimum carrier concentration. The field-effect transistor (FET) technology can turn carrier concentration on a large scale in the same thin film. In addition, theoretical and experimental studies also show that low dimensionality can improve the thermoelectric properties of materials. Based on that, in this project, we use the mechanical method, chemical method, etc. to cleavage SnSe single crystal into thin film, measure electric properties by four-probe method, measure thermal properties in plane via 3-Omega technique, and develop the test of film thermoelectric properties in technology. We study the influence rule of film thickness on thermoelectric properties, and investigate the physical mechanism in combination with modern quantum theory. The optimum thermoelectric properties of a SnSe thin film is achieved by the regulation ability of FET technology in carrier concentration. The results of this project have important scientific significance for elucidating the influence of film thickness and carrier concentration on electrothermal transport as well as microscopic physical mechanism. Moreover, it will provide a new route for enriching the research system and improving thermoelectric performance.

热电材料是一种利用固体中载流子输运产生功率输出的环境友好的新能源材料，在废热回收发电和致冷等领域具有广阔的应用前景。SnSe是热电材料中的明星材料，然而其载流子浓度调控难度大，最佳载流子浓度难以达到。场效应管调控技术可在同一片薄膜中大范围调控载流子浓度。另外，理论与实验研究也表明低维化可提高材料热电性能。基于此，本项目利用机械法、化学法等将SnSe单晶解理成薄膜，以四探针法测量薄膜面内的电学性能，采用3-Omega技术测量薄膜面内的热导率，在技术上完善薄膜热电性能的测试；研究薄膜的厚度对材料热电性能的影响规律，结合现代量子理论探讨相关物理机制；研究通过场效应管栅压调控技术调控薄膜的载流子浓度，优化SnSe薄膜的热电性能，并阐明相关物理机理。该项目成果对阐明薄膜的厚度、载流子浓度与电热输运的影响规律及其微观物理机制具有重要的科学意义，为丰富热电材料研究体系和性能的提升提供了新的空间与途径。

热电材料是一种利用固体中载流子输运产生功率输出的环境友好的新能源材料，在废热回收发电和致冷等领域具有广阔的应用前景。本项目主要目的是开发一套能测试薄膜热电性能的集成测量系统，用于研究场效应管调控的SnSe薄膜的热电性能。目前，本项目主要完成了3-Omega技术对SnSe薄膜面外热导率的设计和实施，初步完成了前期高难度的薄膜热导率技术开发部分，为以后的的持续研究和开发提供了有力的技术条件。同时，基于本项目的资助，我们也做了一些块体热电材料的研究和探索。