非均匀的纳米晶硅(nc-Si)薄膜的横向热伏效应

Transversal thermovoltaic effect between two nc-Si∶a-Si films with different crystallization degree

采用磁控溅射技术在石英衬底上沉积1层200nm厚的非晶硅(a-Si)薄膜,并用真空热蒸发在其上沉积两个横向接触的厚度不同(分别为50和100nm)的Al膜。将已沉积好的薄膜在N2气氛中600℃下退火45min,得到两个横向接触的具有不同晶化程度的纳米晶硅(nc-Si)薄膜。利用X射线衍射(XRD)、Raman光谱、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究了所制备样品的结构特性。由较厚Al膜诱导的nc-Si薄膜的Si晶粒平均尺寸为25nm,晶化率为56%;由较薄Al膜诱导的nc-Si薄膜的Si晶粒平均尺寸为15nm,晶化率为23%。实验发现在没有温度梯度的情况下,这两个不同晶化程度的nc-Si薄膜之间具有横向热伏效应。温度为273K时,其开路电压为1.2mV,短路电流为40nA;当温度达到373K时,其开路电压达到25mV,短路电流达到1.171μA。

Two transversal contacted nanocrystalline Si（nc-Si）∶amorphous Si（a-Si） films with different crystallization degree has been prepared on a quartz substrate by crystallizing a 200nm thick amorphous Si（a-Si） film using two different thick Al films（50 and 100nm） deposited on it, and annealing at 600℃ for 45min, in N2. The structural properties of the prepared films has been studied by XRD, Raman, SEM and TEM. For the nc-Si film induced by thicker Al film the average size of nc-Si is 25nm and its crystallization rate is 56%. For the nc-Si film induced by thinner Al film the average size of nc-Si is 15nm and its crystallization rate is 23%. It is found that there is a transversal thermovoltaic effect between the two nc-Si films, which is uniformly heated in the absence of external temperature gradients. The open circuit voltage and short circuit current is 1. 2mV/40nA at 273K, 25mV/1. 171μA at 373K.