Studies of double-layer transparent conductive films applied for heterojunction solar cell with poly-silicon passivation layers

• Main Authors: CHUANG, LI-YANG, 莊立揚
• Other Authors: LEE, YIH-SHING
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/kmcu65

碩士 === 明新科技大學 === 光電系統工程系碩士班 === 107 === In this thesis, heterojunction silicon solar cell with n-type polycrystalline silicon (poly-Si) passivation layers and using a double-layer transparent conductive films as anti-reflection layers of the heterojunction silicon solar cell were studied. In the experiment, the surface reflectance can be decreased by using such multiple layers with high and low refractive indices values and maintains high transmittance. First, our passivated contact structure for phosphorus-doped n-poly-Si covered ultrathin (~1.7 nm) tunneling oxide layers, crystallizion doping of n-poly and p-poly-Si were prepared by using thermal oxidation and appropriate processing SiH4/PH3 and SiH4/B2H6 ratios, respectively. Finally, a high temperature annealing produces the higher interface passivation effect. The experimental results show that the passivation effect of poly-Si is excellent when the annealing temperature reaches 875°C for 30 minutes, the minority carrier lifetimes of n-poly and p-poly-Silicon are 3224 μs and 4652 μs, respectively. By using the optimum TNO (Nb doping TiO2) and ITO (Indium-tin oxide) experimental conditions, then using optical constants of the ITO and TNO films for Macleod simulation and trends of optical properties for double layers ITO/TNO thickness combination. Then TNO deposited by DC reactive magnetron sputtering on the poly-Si; Later, depositing ITO films on the TNO film after have been by using the optimum ITO experimental conditions. In the experiment, ITO/TNO films have a lower reflectance than the single-layer ITO films in the visible wavelength range, the center wavelength is 550 nm. The optimum thickness ITO/TNO films deposited on the glass substrate is 80/20nm, the lowest reflectance is 11.1%, the optimum thickness ITO/TNO films deposited on the silicon substrate is 70/30nm, the lowest reflectance is 17.4%. The best photon absorption wavelength of 900nm for the crystalline silicon solar cell, the low reflectance for the respective ITO/TNO films thickness of 80/20 and 70/30 nm on the Si substrate are 0.07 and 0.95%. Results show that the reflectance in the near-infrared region has been improvd remarkably by depositing ITO/TNO films on the silicon substrate. According to differences of the refractive indicies between Si and glass substrates, the reflectance in the near-infrared region was obviously improved by the graded refractive indicies lamination effect.