摘要
一种新型的腐蚀剂 ,磷酸钠 (Na3PO4 ·12H2 O)溶液 ,首次被用来腐蚀单晶硅太阳电池。在 70℃下 ,用 3%的磷酸钠 (Na3PO4 ·12H2 O)溶液腐蚀 2 5min就能在硅片表面形成金字塔大小均匀、覆盖率高的绒面结构 ,并且其表面反射率也很低。通过SEM观察发现 :开始时 ,随着腐蚀时间的增加 ,金字塔的密度越来越大 ,最后达到饱和 ;而且对于不同的浓度 ,温度 ,这种饱和时间不同 ;如果腐蚀时间过长 ,金字塔的顶部就会发生崩塌 ,从而导致表面发射率的升高。虽然异丙醇 (IPA)在氢氧化钠 (NaOH)溶液中会明显地改善织构化的效果 ,但是在磷酸钠 (Na3PO4 ·12H2 O)溶液中却会对织构化有很强的负面效应。最后 ,在实验的基础上对腐蚀机理进行了深入地探讨并认为 :择优腐蚀是金字塔形成的最基本的原因 ,而缺陷、PO3 -4 或HPO2 -4 和异丙醇等仅仅是促进大金字塔形成的原因。这种腐蚀剂的成本很低 ,不易污染工作环境且可重复性好 ,所以有可能用于大规模生产。
A new etchant, sodium phosphate tribasic (Na3PO4·12H2O) solution, was firstly applied to texture monocrystalline silicon for solar cells. Uniform pyramids in the wafer of monocrystalline silicon were formed with 3% of sodium phosphate tribasic at 70°C for 25 min. By SEM it was found that the density of pyramid increases with the increase of etching time and reaches saturation. For different etching temperatures and concentrations, the saturated time varies. If the etching time is too long, the top of pyramid will collapse, leading to the rise of reflectance. Although isopropyl alcohol (IPA) plays a great role in the alkaline solution for texture monocrystalline silicon, it makes a negative effect in the sodium phosphate tribasic solution. The mechanism of texturization was discussed. It was found that anisotropic etching is the basic cause of pyramidal formation and defect, and IPA or PO43- is the cause of big pyramid formation. This etchant has the advantages of low cost, no pollution and good reproducibility, so it can be used for large scale production.
出处
《太阳能学报》
EI
CAS
CSCD
北大核心
2002年第3期285-289,共5页
Acta Energiae Solaris Sinica
基金
国家自然科学基金项目 ( 5 9976 0 35 )
教育部高校博士基金
教育部优秀年轻教师基金
关键词
单晶硅
织构
磷酸钠
腐蚀
Etching
Silicon
Sodium compounds
Texturing
