Manufacturing and Characterisation of a Thermoelectric Materials based on Boron Doped Nanocrystalline Diamond Foils

例如，基于塞贝克效应的热电发电机（TEG）可以直接从汽车或发电厂产生的废热中产生电流。现有的TEG材料目前由于其毒性、稀有可用性（碲化铋和碲化铅）或低效率（硅锗）而无法经济使用。单晶和微晶金刚石具有非常高的导热系数（约2000W/mK）和非常低的导电性，因此金刚石似乎不适合作为热电材料。在温度稳定的模板上化学气相沉积硼掺杂金刚石可以制备纳米晶金刚石箔。沉积后，可以控制完整的纳米金刚石层作为纳米金刚石箔的分层。由于其良好的导电性和低导热系数（约2 W/mK），它是一种很有前途的热电材料。纳米金刚石在高温下非常稳定（空气中约600°C，无氧约1100°C）。这些特性应该能够实现高热电效率（ZT值> - 2-3）。在这个项目中，我们希望通过改变HF-CVD工艺参数（压力、甲烷含量、硼含量、涂层温度）来生产硼掺杂纳米晶金刚石箔。热电性能（塞贝克系数，导热系数和导电性）将被测量。此外，应该使用新的掺硼箔（p-导电性）和“差”（低效率）的氮掺杂碳箔（n-导电性）来构建热电发电机并对其进行表征。

Thermoelectric generators (TEG) based on the Seebeck Effect can directly produce electrical current from the waste heat generated by cars or power plants for instance. The established TEG materials currently enable no economical use due to its toxicity, its rare availability (Bismuth- and Lead Tellurides) or its low efficiency (Silicon Germanium).Single crystalline and microcrystalline diamond have a very high thermal conductivity (ca. 2000W/mK) and a very low electrical conductivity, therefore diamond seems to be unsuitable as thermoelectric material. Nanocrystalline diamond foils can be produced by chemical vapour deposition of boron doped diamond on temperature stable templates. After deposition a controlled delamination of the complete nanodiamond layer as nanodiamond foil is possible. It is a promising thermoelectric material, due to its good electrical conductivity and low thermal conductivity (ca. 2 W/mK). Nano diamond is very stable at elevated temperatures (ca. 600°C in air, ca. 1100°C without oxygen). These properties should enable high thermoelectric efficiencies (ZT- value > 2-3). In this project we want to produce boron-dope Nanocrystalline diamond foils with by variation of the HF-CVD process parameters (pressure, methane content, boron content, coating temperature). The thermoelectric properties (Seebeck coefficient, thermal and electrical conductivity) will be measured. Furthermore a thermoelectric generator should be built and characterized by using the new boron-doped foils (p-conductivity) and "poor" (low effiency) N-doped carbon foils (n-conductivity).