Application of heterojunction to Si-based solar cells using photonic nanostructures coupled with vertically aligned Ge quantum dots
Application of heterojunction to Si-based solar cells using photonic nanostructures coupled with vertically aligned Ge quantum dots
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DOI：
10.7567/jjap.54.08ka06
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发表时间：
2015-07
影响因子：
1.5
通讯作者：
I. Takahashi;Y. Hoshi;T. Tayagaki;T. Oikawa;K. Ohdaira;N. Usami
中科院分区：
文献类型：
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作者：
I. Takahashi;Y. Hoshi;T. Tayagaki;T. Oikawa;K. Ohdaira;N. Usami
我们最近开发了一种新的太阳能电池结构，它由光子纳米结构与晶体硅衬底上垂直排列的锗量子点耦合组成。为了制造太阳能电池器件，选择了a-Si:H异质结，因为它的加工温度低于200℃，此时Ge原子不能扩散到Si层中。在这项研究中，我们制定了一个指导方针，以最合适的电池结构，利用锗层的优势，通过制造具有不同结构的异质结太阳能电池。结果表明，在pn结侧制备锗量子点时，吸收在锗量子点中的载流子对输出电流有贡献。因此，发现在Ge点层中存在内置电位对于提取在Ge层中产生的载流子是必要的。此外，在反向偏置条件下，Ge量子点中的载流子输运得到了改善。因此，在我们提出的结构中，锗层中的电场是提高太阳能电池性能的关键参数。
We have recently developed a new structure for solar cells that consists of photonic nanostructures coupled with vertically aligned Ge quantum dots on a crystalline Si substrate. For the fabrication of a solar cell device, a heterojunction with a-Si:H was chosen because its processing temperature is less than 200 °C, at which point Ge atoms cannot diffuse into Si layers. In this study, we developed a guideline for the most appropriate cell structures to take advantage of the Ge layer by fabricating heterojunction solar cells with various structures. As a result, we confirmed that the carriers absorbed in Ge quantum dots contributed output current when Ge quantum dots are fabricated on the pn-junction side. Hence, the presence of built-in potential in a Ge dot layer was found to be necessary to extract the carriers generated in the Ge layer. In addition, carrier transport in Ge quantum dots is improved under conditions of reverse bias. Therefore, the electrical field in the Ge layer is a key parameter to improve solar cell performance in our proposed structure.