Impact of Al Passivation and Cosputter on the Structural Property of β-FeSi₂ for Al-Doped β-FeSi₂/n-Si(100) Based Solar Cells Application

Abstract

The aluminum (Al) doped polycrystalline p-type β-phase iron disilicide (p-β-FeSi2) is grown by thermal diffusion of Al from Al-passivated n-type Si(100) surface into FeSi2 during crystallization of amorphous FeSi2 to form a p-type β-FeSi2/n-Si(100) heterostructure solar cell. The structural and photovoltaic properties of p-type β-FeSi2/n-type c-Si structures is then investigated in detail by using X-ray diffraction, Raman spectroscopy, transmission electron microscopy analysis, and electrical characterization. The results are compared with Al-doped p-β-FeSi2 prepared by using cosputtering of Al and FeSi2 layers on Al-passivated n-Si(100) substrates. A significant improvement in the maximum open-circuit voltage (Voc) from 120 to 320 mV is achieved upon the introduction of Al doping through cosputtering of Al and amorphous FeSi2 layer. The improvement in Voc is attributed to better structural quality of Al-doped FeSi2 film through Al doping and to the formation of high quality crystalline interface between Al-doped β-FeSi2 and n-type c-Si. The effects of Al-out diffusion on the performance of heterostructure solar cells have been investigated and discussed in detail.

Low temperature grown highly texture aluminum alloyed iron silicide on silicon substrate for opto-electronic applications

“…1 shows the XRD spectra of Al alloyed FeSi 2 films for different RTA temperatures. A sharp distinct diffraction peak at 17°is observed for sample annealed at Z600°C conforming the formation of (001) planes of α-FeSi(Al) ternary alloy [2,12,15]. A low intensity peak at 52.8°is also observed corresponding to (003) orientations [15].…”

“…Of these different phases, β-phase FeSi 2 is the only one which is semiconducting in nature and the most researched silicide material due to its promising optoelectronic properties [2,[7][8][9]. In particular, over the last decade, the semiconducting β-Phase FeSi 2 has been a material for keen interest to photovoltaic (PV) community [5,[9][10][11][12]. The β-phase FeSi 2 can be fabricated in labs using simple and easy techniques [6,10] which might be a possible reason for its wide research.…”

Titanium doped cupric oxide for photovoltaic application

“…As reported elsewhere [5,6], the formation of Cu rich interfacial layer and amorphous like isolation layer between copper oxide absorber layer and Si substrate degrades the interface properties at p-CuO/n-Si heterojunction and may intensify the Fermi level pinning effect, which results in large leakage current and low V oc . Formation of interfacial insulation layer is mainly due to the residual oxygen in the sputter chamber and it is also observed for sputter grown beta-phase iron silicide based solar cells [14][15][16].…”

Current Status and Future Prospects of Copper Oxide Heterojunction Solar Cells

“…As the copper oxides provide the suitable band gaps for single junction and tandem solar cells, it is worthwhile to find n-type materials with suitable band gap. Moreover, the sputter deposition technique is industry compatible and suitable for large scale deployment [60,61,62,63,64]. …”