Al_2O_3增强的Co_2-C_（98）/Al_2O_3/Si异质结的光伏效应

摘要

As energy crisis is aggravated,solar cell,as a common form of the development and utilization of solar energy,has attracted more and more attention all over the world.With solar cells developing towards the direction of high efficiency,thin film,non-toxic and rich raw materials,the pure silicon solar cell could not meet these requirements,so the new material and process are imminently required. This paper deals with the photovoltaic effect of the carbon material based on the silicon heterostructure,and its possible application to solar cells.Co_2-C_（98）/Al_2O_3/Si heterostructure with a 4 nm-thick Al_2O_3 layer shows the best photovoltaic effect performance with a short-current density of 18.75 mA/cm~2,an open-circuit voltage of 0.447 V and a power conversion efficiency of 3.27%with AM 1.5 illumination,which is much better than Co_2-C_（98）/Si heterostructure without the Al-2O_3 layer.The effect of Al_2O_3 layer is attributed to the reduction of the interface defects,the suppression of the surface recombination and the enhancement of barrier height,which are proved by the capacitance-voltage and current-voltage measurements under dark condition.This work may shed light on the carbon/silicon based solar cells.%随着能源危机的加剧,太阳能电池作为开发和利用太阳能的一种普遍形式,日益受到世界各国的重视.随着太阳能电池向着高效率、薄膜化、无毒性和原材料丰富的方向发展,单纯的硅系太阳能电池已经无法达到这样的要求,因此新的材料和工艺的开发利用迫在眉睫.本文研究了碳材料在硅异质节上实现光伏效应的改善及其可能在太阳能电池上的应用.采用脉冲激光沉积方法制备的Co_2-C_（98）,Al_2O_3/Si异质结构在标准日光照射（AM1.5,100 mW/cm~2）条件下,可获得0.447 V的开路电压和18.75 mA/cm~2的电流密度,转换效率可达3.27%.通过电容电压特性和暗条件下的电输运性能测量,证明了氧化铝层的引入不但对单晶硅的表面起到了物理钝化作用,减小了反向漏电流,使异质结界面缺陷、界面能级和复合中心减少,还起到了场效应钝化作用,增加了异质结界面的势垒高度,增加了开路电压,使异质结的光伏效应显著增强.