17:15 〜 17:30
▲ [15p-421-15] Improvement of Silicon Nanowire Solar Cells Performance by Micro-grid metal contact
キーワード：nanowire, solar cell, micro-grid
In recent years, with enormous advantages of carrier collection and light absorption, Si nanowire (SiNW) solar cells offer a potential to replace the planar Si solar cells. However, there are still some problems of SiNW solar cells at the present. For instance, normal metal grid would shade around 10% of surface areas which limit the light absorption, especially in the SiNW structures because of larger areas in 3D-array. To improve the performance, better front electrodes need to be pursued. A new method using micro-grid metal contact was investigated here to enhance the front contact and maintain the light absorption.
SiNW arrays were prepared on 525 µm-thick n-type crystalline Si (100) substrates by using AgNO3/HF solution. Then, p-type shell was deposited by CVD. Some other treatments were applied to improve its performance such as rapid thermal annealing and back surface field layer formation.
For making the micro-grid metal contact, photolithography technique was used: First, photoresist layer was spun on the surface of silicon substrate after ITO deposition process. Next, samples were irradiated under UV lamp through a photomask. Then, negative developing the sample and metal deposition were done. Finally, the photoresist was removed to carry out the micro-grid metal contact.
The I-V curves of two type metal grids and the parameters of solar cell performances. Owning to the shorter transfer distance in micro-grid, the light-generated carriers are easier collected without recombining and higher collection probability increases higher light-generated current. As the results, the short-circuit current density (JSC) was increased from 19.28 to 27.84 mA/cm2, open-circuit voltage (VOC) and fill factor (FF) were kept at the same level. Finally, the solar cell was achieved a 45% improvement and enhance efficiency from 7.5 % to 10.9%.
SiNW arrays were prepared on 525 µm-thick n-type crystalline Si (100) substrates by using AgNO3/HF solution. Then, p-type shell was deposited by CVD. Some other treatments were applied to improve its performance such as rapid thermal annealing and back surface field layer formation.
For making the micro-grid metal contact, photolithography technique was used: First, photoresist layer was spun on the surface of silicon substrate after ITO deposition process. Next, samples were irradiated under UV lamp through a photomask. Then, negative developing the sample and metal deposition were done. Finally, the photoresist was removed to carry out the micro-grid metal contact.
The I-V curves of two type metal grids and the parameters of solar cell performances. Owning to the shorter transfer distance in micro-grid, the light-generated carriers are easier collected without recombining and higher collection probability increases higher light-generated current. As the results, the short-circuit current density (JSC) was increased from 19.28 to 27.84 mA/cm2, open-circuit voltage (VOC) and fill factor (FF) were kept at the same level. Finally, the solar cell was achieved a 45% improvement and enhance efficiency from 7.5 % to 10.9%.