Antireflective and passivation properties of the photovoltaic structure with Al2O3 layer of different thickness

Purpose The purpose of this study is to verify the possibility of applying alumina (Al2O3) as the passivation and antireflective coating in silicon solar cells. Design/methodology/approach Model of a studied structure contains the following layers: Al2O3/n+/n-type Si/p+/Al2O3. Optical parameters of the aluminium oxide films on silicon wafers were measured in the range of wavelengths from 250 to 1,400 nm with a spectrophotometer Perkin Elmer Lambda 900. The minority carrier lifetime at the start of the n-type Si base material and after each of the next technological process was analysed by a quasi-steady-state photoconductance technique. The electrical parameters of the solar cells fabricated with four different thickness of the Al2O3 layer were determined on the basis of the current-voltage (I-V) characteristics. The silicon solar cells of 25 cm2 area and 300 µm thickness were investigated. Findings The optimum thickness of alumina as passivation layer is 90 nm. However, considering also antireflective properties of the first layer of a photovoltaic cell, the best structure is silicon with alumina passivation layer of 30 nm thickness and with TiO2 antireflective coatings of 60 nm thickness. Such solution has allowed to produce the cells with the fill factor of 0.77 and open circuit voltage of 618 mV. Originality/value Measurements confirmed the possibility of applying the Al2O3 as a passivation and antireflective coating (obtained by atomic layer deposition method) for improving the efficiency of solar cells.

[1]  H. Savin,et al.  20.8% industrial PERC solar cell: ALD Al2O3 rear surface passivation, efficiency loss mechanisms analysis and roadmap to 24% , 2017 .

[2]  Mari Juel,et al.  Boron liquid solution deposited by spray method for p-type emitter formation in crystalline Si solar cells , 2016, Electron Technology Conference.

[3]  R. Socha,et al.  The liquid phosphorus source for Si solar cells fabrication , 2016 .

[4]  Taehyeon Kim,et al.  Bifacial solar photovoltaics – A technology review , 2016 .

[5]  A. Fave,et al.  Characterization of Al2O3 Thin Films Prepared by Thermal ALD , 2015 .

[6]  Stacey F. Bent,et al.  Atomic layer deposition in nanostructured photovoltaics: tuning optical, electronic and surface properties. , 2015, Nanoscale.

[7]  A. Albadri.  Characterization of Al2O3 surface passivation of silicon solar cells , 2014 .

[8]  Stacey F. Bent,et al.  A brief review of atomic layer deposition: from fundamentals to applications , 2014 .

[9]  S. Steingrube,et al.  Advances in the Surface Passivation of Silicon Solar Cells , 2012 .

[10]  B. Sopori,et al.  Studies on Backside Al-Contact Formation in Si Solar Cells: Fundamental Mechanisms , 2009 .

[11]  Wmm Erwin Kessels,et al.  Surface passivation of high‐efficiency silicon solar cells by atomic‐layer‐deposited Al2O3 , 2008 .

[12]  T. Stapiński,et al.  a-Si:C:H and a-Si:N:H Thin Films Obtained by PECVD for Applications in Silicon Solar Cells , 2008 .

[13]  M. Hitchman,et al.  Chemical Vapour Deposition: Precursors, Processes and Applications , 2008 .

[14]  Piotr Panek,et al.  Reduction of surface reflectivity by using double porous silicon layers , 2003 .

[15]  R. Sinton,et al.  On the use of a bias-light correction for trapping effects in photoconductance-based lifetime measurements of silicon , 2001 .

[16]  R. Hezel,et al.  Low‐Temperature Surface Passivation of Silicon for Solar Cells , 1989 .