Optical properties of porous Si/PECVD SiN_X:H reflector on single crystalline Si for solar cells

Abstract

The improvement of optical confinement on the back crystalline silicon solar cell is one of the factors leading to its better performance. Porous silicon (PS) layer can be used as a back reflector (BR) in solar cells. In this work, single layers of porous silicon were grown by electrodeposition on a single crystalline silicon substrate. The measurement of the total reflectivity (R T ) on Si/PS surface showed a significant improvement in optical confinement compared to that measured on Si/standard Al back surface field (BSF). The internal reflectivity (R B ) extracted from total reflectivity measurements achieved 86 % for the optimized single PS layer (92 nm thick layer with 60 % porosity) in the wavelength range between 950 and 1200 nm. This improvement was estimated as more than 17 % compared to that measured on the surface of Si/BSF Al contact. To improve the stability and passivation properties of PS layer BR, silicon nitride layer (SiN x ) was deposited by PECVD on a PS layer. The maximum measured total reflectivity for PS/SiN x achieved approximately 56 % corresponding to an improved R B of up to 83 %. The PS formation process in combination with the PECVD SiN x , can be applied in the photovoltaic cell technology and offer a promising technique to produce high-efficiency and low-cost c-Si solar cells.

Use of the Richardson extrapolation in optics of inhomogeneous layers: Application to optical characterization

“…The non‐stoichiometric silicon nitride films were selected for the optical characterization because they have considerable utilization in practice, such as the antireflection coatings in silicon solar cells and reflectors on the back sides of these solar cells . They are also used for production of interference filters and reflectors in optics industry.…”

Temperature-Dependent Photoluminescence Study of Porous Gap

“…Porous silicon was discovered in 1957 by Uhlin due to the observation of visible room-temperature luminescence [1]. This material plays an important role in many technologies such as optical and photonic devices [2,3], sensors [4][5][6], (bio) chemical reactors [7] and super capacitors [8]. Like silicon, III-V semiconductor such as gallium phosphide has been investigated in the form of porous structure [9][10][11][12][13].…”