| AVS 65th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Tuesday Sessions |
| Session PS-TuP |
| Session: | Plasma Science and Technology Division Poster Session |
| Presenter: | Hugo Alvarez, University of Campinas, Brazil |
| Authors: | H.S. Alvarez, University of Campinas, Brazil G.L. Bertão, University of Campinas, Brazil A.R. Silva, University of Campinas, Brazil F.H. Ciodin, University of Campinas, Brazil J.A. Diniz, University of Campinas, Brazil |
| Correspondent: | Click to Email |
In this work, silicon based heterojunction (SHJ) solar cells were fabricated without a intrinsic layer using a 200 nm a-Si:H p+ layer deposited by Electron Cyclotron Resonance-Chemical Vapor Deposition (ECR-CVD) system on to p+-c-Si substrate. The electrical parameters of the obtained solar cells, such as efficiency, are related to the effects of: i) radio-frequency (RF) chuck power, used during the deposition of amorphous silicon (a-Si:H) Electron Cyclotron ECR-CVD, in the incorporation of H into the a-Si:H films for different RF powers; ii) Silicon micro-channels, which were fabricated in the back-side substrate with the solar cells.
The films were deposited using a ECR power of 500W, pressure of 4mTorr, substrate temperature of 20 °C, gas flows of SiH4 and Ar, 200 and 20 sccm and 20 minutes and RF power of 1, 3 and 5W. To create the p+ layer, the samples were boron implanted and annealed in a RTA process. Back and front aluminum contacts of 500 nm were deposited by sputtering and a thin layer of silicon oxide for passivation and an antireflective coating of silicon nitrite was deposited in the ECR for PV Cells efficiency measurements. The back-side contacts were corroded in circular dots (200 µm of diameter) and used as mask to define the silicon micro-channels using ICP (Inductively Coupled Plasma) plasma etching based on SF6/Ar gas mixture. This SHJ solar cells were fabricated and the current density versus voltage curves in illuminated (AM 1.5) condition were measured. Before the microchannel etching, all solar cells, presented lowest efficiencies of about 0.001%. After the formation of the Micro-Channels (depths of about 7.5 µm and 8.2µm, for 10 and 40 minutes, respectively) using ICP plasma etching increased these values at least one order of magnitude. The maximum of 0.4% of efficiency was obtained for the SHJ cell, which was fabricated with the a-Si:H film of 3W RF power and with micro-channel in back-side, using 10 minutes of ICP etching. In the future, we intend to fabricate a microfluidic system to introduce the fluid into the Micro-Channels to cool and to increase the efficiency values of solar cells.