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材料由于其毒性、稀有的可获得性(铋和铅碲化物)或低效率(硅锗)，目前不能经济地使用。单晶和微晶金刚石具有非常高的导热系数(约2000W/MK)和非常低的导电率，因此钻石似乎不适合作为热电材料。在温度稳定的模板上，用化学气相沉积法制备了掺硼金刚石纳米晶薄膜。在沉积之后，完全的纳米金刚石层作为纳米金刚石箔的可控分层是可能的。由于其良好的导电性和较低的热导率(约2W/MK)，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-Value&gt；2-3)。在本项目中，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)来制备掺硼纳米晶金刚石薄膜。将测量热电性能(Seebeck系数、热导率和电导率)。此外，还应建立热电发电机，并使用新的掺硼薄膜(p-电导)和“差”(低效)氮掺杂碳箔(n-电导)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).