Development of Amorphous- and Crystalline-Si Quantum Dots Embedded ZnO Thin Films for Photovoltaic Device Application

• Main Authors: Liu, Chuan-Cheng, 劉權政
• Other Authors: Lee, Po-Tsung
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/zkcj6n

碩士 === 國立交通大學 === 光電工程學系 === 101 === Recently, the silicon quantum dot (Si QD) thin films have been extensively studied and applied to the popular optoelectronics due to the widely tunable bandgap and unique optical properties. For example, the Si QD thin films have the great potential for photovoltaic (PV) applications because it can solve the optical loss problem in the short-wavelength range for the Si-based solar cells (SCs). So far, the Si-based dielectric materials are used as the matrix material of Si QD, and the PV properties has been demonstrated. However, the overall PV properties are still limited by the naturally high resistance of the Si-based dielectric matrix materials. In order to solve the bottleneck of the Si QD thin films applying to SC application, we propose to use ZnO as the matrix material of Si QDs since the ZnO thin film is a semiconductor material with wide bandgap, high transparency, and tunably electrical properties. These advantages are potential in improving the electro-optical properties of the Si QD thin films for SC application. In this study, the Si QD embedded ZnO thin films are fabricated by sputtering method and deposited by a [ZnO/Si] multilayer structure with 20 pairs. The self-assembled Si nano-clusters are formed in ZnO matrix by high Si sputtering power and thin Si layer thickness during deposition. The crystalline, optical, and electrical properties of the samples annealed at different temperatures are investigated and discussed. Besides, the electro-optical properties of the amorphous- and crystalline-Si QD thin films are also further improved by tuning the annealing time and using the H2 annealing process. The all Si-based third generation solar cells with high efficiency and low cost can be highly expected by integrating the Si QD embedded ZnO thin films and the a- or μc-Si thin films in the future.