微晶硅锗薄膜作为近红外光吸收层在硅基薄膜太阳电池中的应用  

Developments of μc-Si_(1-x)Ge_x:H thin films as near-infrared absorber for thin film silicon solar cells

作　　者：曹宇[1,2] 薛磊[1] 周静[3] 王义军[1] 倪牮[2] 张建军[2] 

机构地区：[1]东北电力大学电气工程学院,吉林132012 [2]南开大学电子信息与光学工程学院,天津300071 [3]东北电力大学化学工程学院,吉林132012

出　　处：《物理学报》2016年第14期209-216,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61377031;51442002;61404073);吉林省教育厅"十二五"科学技术研究项目(批准号:2015253)资助的课题~~

摘　　要：采用射频等离子体增强化学气相沉积技术,制备了具有一定晶化率不同Ge含量的氢化微晶硅锗(μcSi1-xGex:H)薄膜.通过Ⅹ射线荧光谱、拉曼光谱、X射线衍射谱、傅里叶红外谱、吸收系数谱和电导率的测试,表征了μc-Si_(1-x)Ge_x:H的材料微结构随Ge含量的演变.研究表明:提高Ge含量可以增强μc-Si_(1-x)Ge_x:H薄膜的吸收系数.将其应用到硅基薄膜太阳电池的本征层中可以有效提高电池的短路电流密度(J_(sc)).特别是在电池厚度较薄或陷光不充分的情况下,长波响应的提高会更为显著.应用ZnO衬底后,在Ge含量分别为9%和27%时,μc-Si_(1-x)Ge_x:H太阳电池的转换效率均超过了7%.最后,将μc-Si_(1-x)Ge_x:H太阳电池应用在双结叠层太阳电池的底电池中,发现μc-Si_(0.73)Ge_(0.27):H底电池在厚度为800 nm时即可得到比1700 nm厚微晶硅(μc-Si:H)底电池更高的长波响应.以上结果体现μc-Si_(1-x)Ge_x:H太阳电池作为高效近红外光吸收层,在硅基薄膜太阳电池中应用的前景.Hydrogenated microcrystalline silicon germanium（μc-Si（1-x）Gex：H） thin films have been developed as alternative bottom sub-cell absorbers for multi-junction thin film silicon solar cells due to their narrower band-gaps and higher absorption coefficients than conventional hydrogenated microcrystalline silicon（μc-Si：H） thin films. However, since the structure complexity was increased a lot by Ge incorporation, the influences of μc-Si（1-x）Gex：H film properties on Ge composition have not been understood yet. In this work, μc-Si（1-x）Gex：H thin films with various Ge content and similar crystalline volume fraction are fabricated by radio frequency plasma-enhanced chemical vapor deposition（RF-PECVD）. The evolutions of μc-Si（1-x）Gex：H material properties by Ge incorporation are characterized by X-ray fluorescence spectrometry, Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, absorption coefficient spectrum, and conductivity measurement. The results show that the properties of μc-Si（1-x）Gex：H thin films are strongly determined by Ge content. With the increase of Ge content, the absorption coefficient,（111） grain size,microstructure factor, and dark conductivity of μc-Si（1-x）Gex：H thin films increase, while the H content,（220） grain size,and photosensitivity of μc-Si（1-x）Gex：H thin film decrease. Then, μc-Si（1-x）Gex：H is used as the intrinsic layer in the single junction solar cells. The performances of μc-Si（1-x）Gex：H solar cells with different Ge content and two types of transparent conductive oxide（SnO2 and ZnO） substrates are systematically studied. The results indicate that althoughμc-Si（1-x）Gex：H thin films become more defective and less compact with Ge incorporation, μc-Si（1-x）Gex：H solar cells exhibit a significant improvement in near-infrared response, especially under the circumstances of thin cell thickness and inefficient light trapping structure. Meanwhile, by using Zn O substrat

关 键 词：氢化微晶硅锗 近红外响应 硅基薄膜太阳电池 等离子体增强化学气相沉积 

分 类 号：TM914.42[电气工程—电力电子与电力传动] O484[理学—固体物理]