嵌入a-Si:H薄层的μc-Si/c-Si pn异质结太阳能电池热平衡态特性的数值模拟分析

应用计算机数值模拟方法计算p+(μc-Si:H)/n(c-Si)及p+(μc-Si:H)/i(a-Si:H)/n(c-Si)异质结太阳能电池中的电场强度分布,说明μc-Si/c-Si异质结电池制造中μc-Si:H膜厚选择,进而对嵌入a-Si:H薄层的μc-Si/c-Si异质结太阳能电池设计进行分析,包括a-Si:H薄层p型掺杂效应及本底单晶硅的电阻率选择,最后讨论μc-Si/c-Si异质结太阳能电池稳定性.     

高效率n-nc-Si∶H/p-c-Si异质结太阳能电池

采用热丝化学气相沉积技术(HWCVD),系统地研究了纳米晶硅层(尤其是本征缓冲层)的晶化度以及晶体硅表面氢处理时间对nc-Si∶H/c-Si异质结太阳能电池性能的影响,通过C-V和C-F测试分析了不同氢处理时间和本征缓冲层氢稀释度对nc-Si∶H/c-Si界面缺陷态的影响,运用高分辨透射电镜观察了不同的本征缓冲层晶化度的nc-Si∶H/c-Si异质结太阳能电池的界面,优化工艺参数,在p型CZ晶体硅衬底上制备出转换效率为17.27%的n-nc-Si∶H/i-nc-Si∶H/p-c-Si异质结电池.     

高效率n-nc-Si:H/p-c-Si异质结太阳能电池

采用热丝化学气相沉积技术(HWCVD),系统地研究了纳米晶硅层(尤其是本征缓冲层)的晶化度以及晶体硅表面氢处理时间对nc-Si∶H/c-Si异质结太阳能电池性能的影响,通过C-V和C-F测试分析了不同氢处理时间和本征缓冲层氢稀释度对nc-Si∶H/c-Si界面缺陷态的影响,运用高分辨透射电镜观察了不同的本征缓冲层晶化度的nc-Si∶H/c-Si异质结太阳能电池的界面,优化工艺参数,在p型CZ晶体硅衬底上制备出转换效率为17.27%的n-nc-Si∶H/i-nc-Si∶H/p-c-Si异质结电池.     

P型硅衬底异质结太阳电池的优化设计

采用Afors-het软件模拟分析了结构为TCO/a-Si:H(n)/a-Si:H(i)/c-Si(p)/a-Si:H(p+)/Ag的p型硅衬底异质结太阳电池的性能,研究了各层厚度、带隙、掺杂浓度以及界面态密度等结构参数和物理参数对电池性能的影响。通过模拟优化,结合理论分析和实际工艺,得到合适的各结构参数取值。采用厚度薄且掺杂高的窗口层,嵌入本征层以钝化异质结界面缺陷,合理利用背场对于少子的背反作用,获得了较佳的太阳电池综合性能:开路电压Voc为678.9mV、短路电流密度Jsc为38.33mA/cm2、填充因子FF为84.05%、转换效率η为21.87%。     

透明导电氧化膜的功函数对 μc-Si:H(n)/c-Si(p)异质结太阳能电池性能影响的数值模拟

用AFORS-HET软件分析了透明导电氧化膜(Transparent Conductive Oxide,TCO)的功函数对μc-Si∶H(n)/c-Si(p)异质结太阳能电池性能的影响.模拟结果表明,透明导电氧化膜的功函数会强烈影响太阳能电池的性能如Voc和FF.当透明导电氧化膜的功函数在TCO/μc-Si∶H(n)界面小于4.4 eV、μc-Si∶H(n)发射层的厚度为6 nm,透明导电氧化膜的功函数在μc-Si∶H(p+)/TCO界面大于5.2 eV且透明导电氧化膜为ZnO时,模拟的具有纹理结构的TCO/μc-Si∶H(n)/a-Si∶H(i)/c-Si(p)/a-Si∶H(i)/μc-Si∶H (p+)/TCO太阳能电池的转换效率达到了23.78％(Voc:758.6 mV,Jsc:40.94mA/cm2,FF:76.58％).这表明μc-Si∶H(n)/c-Si(p)异质结太阳能电池的性能与透明导电氧化膜的功函数紧密相关,通过透明导电氧化膜的功函数可以提高太阳能电池的效率.     

Optimization of n/i and i/p buffer layers in n-i-p hydrogenated microcrystalline silicon solar cells

Hydrogenated microcrystalline silicon （μc-Si：H） intrinsic films and solar cells with n-i-p configuration were prepared by plasma enhanced chemical vapor deposition （PECVD）. The influence of n/i and i/p buffer layers on the μc-Si：H cell performance was studied in detail. The experimental results demonstrated that the efficiency is much improved when there is a higher crystallinity at n/i interface and an optimized a-Si：H buffer layer at i/p interface. By combining the above methods, the performance of μc-Si：H single-junction and a-Si：H/μc-Si：H tandem solar cells has been significantly improved.     

异质结硅太阳能电池a—Si：H薄膜的研究

通过应用Scharfetter-Gummel数值求解Poisson方程，对热平衡态P^ （a-Si:H)/n(c-Si)异质结太阳能电池进行计算机数值模拟分析。结果指出，采用更薄P^ (a-Si：H）薄膜设计能有效增强光生载流子的传输与收集，从而提高a-Si/c-Si异质结太阳能电池的性能。同时，还讨论了P^ (a-Si:h)薄膜中P型掺杂浓度对光生载流了传输与收集的影响。高强茺光照射下模拟，计算表明，a-Si/c-Si异质结结构太阳能电池具有较高光稳定性。     

高效硅基异质结太阳能电池的模拟

a-Si:H/c-Si异质结太阳能电池的基本参数,如层厚度、掺杂浓度、a-Si:H/c-Si界面缺陷、功函数等是影响载流子传输特性和电池效率的关键因素。在本文中,利用AFORS-HET程序,研究了这些参数与a-Si:H/c-Si电池的性能的关联性。最后,具有TCO/n-a-Si:H/i-a-Si:H/p-c-Si/p -a-Si:H/Ag结构的太阳能电池的最优化性能被获得,其光电转换效率为27.07%（VOC: 749 mV, JSC: 42.86 mA/cm2, FF: 84.33%）。深入地了解异质结电池的输运特性,对进一步提高电池的效率有很大的帮助,同时对实际太阳能电池的制造也能提供有益的指导。     

基于c-Si(P)衬底的a-Si/c-Si异质结模拟研究

本文中研究了影响 a-Si/c-Si 异质结界面复合的主要因素： 表面固定电荷 ,缺陷态载流子俘获界面： ,以及界面缺陷态密度 。当缺陷能级 接近c-Si本征能级,且 满足时,缺陷态复合中心复合速度达到最大。AFORS-HET 软件模拟显示, a-Si/c-Si界面能带不连续显著影响电池Voc、界面缺陷态密度大于1*1010 cm-2.eV-1时,界面态密度的增加会严重降低电池Voc,但其对电池电流密度影响不大。对于c-Si (P)/a-Si (P ) 结构异质结,C-Si衬底的势垒 和a-Si材料内的势垒 对降低c-Si (P)/a-Si (P ) 结构的接触电阻和界面复合速度,表现各不相同。     

a-SiC/c-Si异质结太阳能电池设计分析

通过应用Scharfetter-Gummel解法数值求解Poisson方程,对热平衡态a-SiC/c-Si异质结太阳能电池进行计算机数值模拟,详细分析不同制备条件下a-SiC/c-Si异质结太阳能电池的能带结构和电池中电场强度分布,指出采用更薄p+(a-SiC∶H)薄膜和在pn异质结嵌入i(a-Si∶H)缓冲薄层设计能有效增强光生载流子的传输与收集,从而提高a-SiC/c-Si异质结太阳能电池的性能,而高强度光照射下模拟计算表明,a-SiC/c-Si异质结太阳能电池具有较高光稳定性.     

Influence of the initial transient state of plasma and hydrogen pre-treatment on the interface properties of a silicon heterojunction fabricated by PECVD

Amorphous/crystalline silicon heterojunctions(a-Si:H/c-Si SHJ) were prepared by plasma-enhanced chemical vapor deposition(PECVD).The influence of the initial transient state of the plasma and the hydrogen pre-treatment on the interfacial properties of the heteroj unctions was studied.Experimental results indicate that: (1) The instability of plasma in the initial stage will damage the surface of c-Si.Using a shutter to shield the substrate for 100 s from the starting discharge can prevent the influence of the instable plasma process on the Si surface and also the interface between a-Si and c-Si.(2) The effect of hydrogen pre-treatment on interfacial passivation is constrained by the extent of hydrogen plasma bombardment and the optimal time for hydrogen pre-treatment is about 60 s.     

An a-Si:H vacuum-compatible photoresist process for fabricating device structures in HgCdTe

A process for transferring patterns into HgCdTe epilayers using a hydrogenated amorphous silicon (a-Si:H) photomask has been demonstrated. a-Si:H films were grown using plasma enhanced chemical vapor deposition (PECVD). A latent image of a projected mask pattern was created at the a-Si:H surface by ultraviolet enhanced oxidation in the load lock of the PECVD vacuum chamber. This image was transformed into a mask by hydrogen plasma removal of the unexposed areas. A hydrogen plasma etch selectivity value greater than 500:1 for oxide and a-Si:H allows patterns as thick as 700 nm to be generated. a-Si:H masks were used to create arrays of mesas in planar HgCdTe epilayers by etching in an electron cyclotron resonance (ECR) plasma reactor. Etch selectivity between a-Si:H and HgCdTe during an ECR hydrogen plasma etch was measured to be greater than 18:1. R_oA values > 10³ were obtained for mid-wavelength infrared diodes made from HgCdTe heterojunctions using a-Si:H masks.     

Passivation of p-n junction in crystalline silicon by amorphous silicon

Hydrogenated amorphous silicon, a-Si:H, is shown to be an excellent passivant for crystalline silicon (c-Si) p-n junctions. A two-orders-of-magnitude reduction in reverse leakage current from that of a typical thermal oxide passivated junction is obtained. This is achieved through a lowering of the interface state density by hydrogenation of the c-Si surface. Superior bias-temperature stability of the passivated junctions also is observed. There is evidence that the hydrogen in the bulk of the a-Si:H can act as a hydrogen reservoir for rehydrogenation of the interface between c-Si and a-Si:H. Thermal stability of the a-Si:H is adequate for temperatures up to 500°C for 30 min, which is sufficient for most device-processing requirements. Above 550°C, significant dehydrogenation from both the interface and the bulk a-Si:H regions and an increase in leakage are observed. The passivation properties were assessed through studies of the current-voltage and current-temperature characteristics of the p-n junctions.     

Pd/a-Si:H界面的光电子能谱研究

本文利用光电子能谱(XPS、UPS)技术研究了Pd淀积层与离子注入制备的a-Si∶H层组成的系统.本工作分析了Pd/a-Si∶H的界面键合状态及组分分布的变化对价带谱与芯能级谱的影响,并与Pd/C-Si系统的结果进行了比较.结果表明:Pd/a-Si∶H界面具有与Pd/C-Si界面相似的电子结构;但是,Pd原子在a-Si∶H中具有较大的扩散速率,因此,处于更富Si的环境中。     

Optimization of n/i and i/p buffer layers in n-i-p hydrogenated microcrystalline silicon solar cells

Hydrogenated microcrystalline silicon (μc-Si:H) intrinsic films and solar cells with n-i-p configuration were prepared by plasma enhanced chemical vapor deposition (PECVD). The influence of n/i and i/p buffer layerson the μc-Si:H cell performance was studied in detail. The experimental results demonstrated that the efficiency is much improved when there is a higher crystallinity at n/i interface and an optimized a-Si:H buffer layer at i/p interface. By combining the above methods, the performance ofμc-Si:H single-junction and a-Si:H/μc-Si:H tandemsolar ceils has been significantly improved.     

PECVD沉积微晶硅薄膜过程中氢原子对透明导电膜的影响

研究了等离子体放电过程中氢原子对单层SnO2和SnO2/ZnO双层透明导电膜的影响.发现当衬底温度超过150℃,H等离子体处理使SnO2薄膜的透光率显著降低.当在SnO2薄膜表面沉积一层ZnO时,既使ZnO膜的厚度为50nm,也可有效地抑制H原子对SnO2的还原效应,并在SnO2/ZnO双层膜上制备了转换效率为3.8%的微晶硅薄膜太阳电池.     

a-Si/c-Si异质结结构太阳能电池设计分析

通过应用 Scharfetter- Gum mel解法数值求解 Poisson方程 ,对热平衡态 a- Si/ c- Si异质结太阳能电池进行计算机数值模拟分析 ,着重阐述在 a- Si/ c- Si异质结太阳能电池中嵌入 i( a- Si:H)缓冲薄层的作用 ,指出采用嵌入 i( a- Si:H )缓冲薄层设计能有效增强光生载流子的传输与收集 ,从而提高 a- Si/ c- Si异质结太阳能电池的性能 ,同时还讨论 p+ ( a- Si:H)薄膜厚度和 p型掺杂浓度对光生载流子传输与收集的影响 ,而高强度光照射下模拟计算表明 ,a- Si/ c- Si异质结结构太阳能电池具有较高光稳定性     

a-Si:H/a-SiN_x:H多层膜界面的研究

<正> 尽管过去几年对非晶半导体多层膜及其界面对多层膜传输性能影响的研究甚多,然而对于界面缺陷态的特性及其密度了解甚少。不同的测量方法得到的a-Si:H/a-SiNx:H界面缺陷态密度可从1010变到1012cm-2。这一实验结果反映了每一测试方法仅能探测某些能级的缺陷,在某些情况下可能是不同类的缺陷。非晶硅系材料都包含有氢。已发现,在多层膜的沉积过程中,由于组成多层膜的子层间应力释放的需要以及两子层材料的氢扩散系数不同而