Lee Woon-Jin, Park Gye-Choon, Choi Chel-Jong, Yang O-Bong
J Nanosci Nanotechnol. 2017 Apr;17(4):2682-684. doi: 10.1166/jnn.2017.13365.
We report on the co-diffused bifacial N-type solar cells based on N-type Si wafers using the process of spin on doping (SOD, phosphorous source) and boron tribromide (BBr₃) diffusion by atmospheric pressure chemical vapor deposition (APCVD). For bifacial co-diffusion, a phosphorous layer was deposited by SOD on the rear side of N-type Si wafer and a BBr₃ as boron dopant source deposited by APCVD. Co-diffusion process was controlled by changing the flowrate of carrier N₂ gas and drive-in temperatures. It was found that the fabricated bifacial co-diffused N-type solar cell with 2% H₃PO₄ doping, the flowrate of N₂ carrier gas of 15 slm and drive-in temperature at 930°C exhibited the highest conversion efficiency of 15.8% with high open circuit voltage (V(oc)) of 593 mV. As compared to high H₃PO₄ concentrations (5% and 9%), the low H₃PO₄ concentration of SOD showed the higher sheet resistance and decreased in the thickness of N + emitter layer, resulting in the high V(oc), shunt resistance, fill factor and conversion efficiency of solar cells.
我们报道了基于N型硅片的共扩散双面N型太阳能电池，采用旋涂掺杂（SOD，磷源）工艺以及通过常压化学气相沉积（APCVD）进行三溴化硼（BBr₃）扩散。对于双面共扩散，通过SOD在N型硅片背面沉积一层磷层，并通过APCVD沉积BBr₃作为硼掺杂源。通过改变载气N₂的流量和推进温度来控制共扩散过程。结果发现，制备的掺杂2% H₃PO₄、N₂载气流量为15 slm且推进温度为930°C的双面共扩散N型太阳能电池，展现出最高15.8%的转换效率以及593 mV的高开路电压（V(oc)）。与高H₃PO₄浓度（5%和9%）相比，SOD的低H₃PO₄浓度表现出更高的薄层电阻，且N +发射极层厚度减小，从而导致太阳能电池具有高V(oc)、并联电阻、填充因子和转换效率。
