Numerical simulation and optimization of Si/BaSi₂ heterojunction and BaSi₂ homojunction solar cells

Abstract

High light absorption material BaSi2 based heterojunction and homojunctin solar cells were simulated with the program AMPS (analysis of microelectronic and photonic structures)-1D in order to thoroughly understand the mechanism for further improvement in conversion efficiency. Simulation results demonstrated that p+-Si/n-BaSi2 heterojunction solar cells exhibited superior photoelectric performances as compared with n+-Si/p-BaSi2 solar cells. A high conversion efficiency up to of 22.7% were achieved by p+-Si (100 nm, NA = 5 × 1019 cm−3)/n-BaSi2 (2000 nm, ND = 1 × 1018 cm−3) heterojunction solar cell. For BaSi2/BaSi2 homojunction solar cells, the window layer should be designed as thin with large scale uniformity and high quality in achieving high efficiency. Both n+-BaSi2 (5 nm, ND = 5 × 1019 cm−3)/p-BaSi2 (2000 nm, NA = 1 × 1017 cm−3) homojunction and p+-BaSi2 (5 nm, NA = 5 × 1019 cm−3)/n-BaSi2 (2000 nm, ND = 1 × 1017 cm−3) homojunction solar cells gave out a high conversion efficiency of 22.5%. Both donor-like defects in p-BaSi2 and acceptor like defects in n-BaSi2 light absorption layers were identified to significantly influence the solar cell performance that all parameters deteriorated severely under high bulk defect density. Moreover, p+-Si/n-BaSi2 solar cell was more sensitive to high level interface trap defects on account of the sharp dropping down of Eff under high interface trap density over 5 × 1012 cm−2. This work provided insight essential guidance for device design and optimization in achieving high efficiency silicide solar cell with low cost.

Design and Simulation of FeSi2‐Based Novel Heterojunction Solar Cells for Harnessing Visible and Near‐Infrared Light

“…More recently, it has been reported that the orthorhombic barium disilicide (β‐BaSi 2 ) can be applied as the best BSF layer for performance enhancement in CIGS‐based solar cells . The potential of BaSi 2 for solar cell applications has also been reported by many groups …”

Demonstration of B-ion-implanted p-BaSi2/n-Si heterojunction solar cells

“…[15][16][17] These properties meet the requirement of high-η thin-film solar cells. Based on the results of such basic research to date, various types of BaSi 2 solar cells have been proposed [18][19][20][21][22][23][24] and fabricated in the form of BaSi 2 /Si, [25][26][27][28][29] BaSi 2 -pn, 30) and n-ZnO/p-BaSi 2 , 31,32) and SnS/BaSi 2 33) by thin-film growth methods such as molecular beam epitaxy (MBE), vacuum evaporation, and sputtering.…”

Recent Progress Toward Realization of High‐Efficiency BaSi2 Solar Cells: Thin‐Film Deposition Techniques and Passivation of Defects

“…[38,39] By positron annihilation spectroscopy, [39] it has been revealed that the electron concentration increases to %10 18 cm À3 with increasing vacancy-type defects [38] when the Ba/Si atomic ratio is far from the stoichiometric ratio. In addition, novel device structures have been proposed, [40][41][42][43][44][45][46][47][48][49][50] and passivation of defects in BaSi 2 has been demonstrated by atomic-hydrogen (H) [51][52][53][54][55][56] and carbon (C) doping. [27,30,57] For deposition techniques, vacuum evaporation of BaSi 2 granules [21][22][23][24][25] and sputtering of BaSi 2 targets [26][27][28][29][30] or cosputtering of Si and Ba targets [31] are suitable to form BaSi 2 films for large-scale deployment on inexpensive substrates like SiO 2 .…”