Advances in Evaporated Solid‐Phase‐Crystallized Poly‐Si Thin‐Film Solar Cells on Glass (EVA)

Abstract

Recommended by John PernPolycrystalline silicon thin-film solar cells on glass obtained by solid-phase crystallization (SPC) of PECVD-deposited a-Si precursor diodes are capable of producing large-area devices with respectable photovoltaic efficiency. This has not yet been shown for equivalent devices made from evaporated Si precursor diodes ("EVA" solar cells). We demonstrate that there are two main problems for the metallization of EVA solar cells: (i) shunting of the p-n junction when the air-side metal contact is deposited; (ii) formation of the glass-side contact with low contact resistance and without shunting. We present a working metallization scheme and first current-voltage and quantum efficiency results of 2 cm 2 EVA solar cells. The best planar EVA solar cells produced so far achieved fill factors up to 64%, series resistance values in the range of 4-5 Ωcm 2 , short-circuit current densities of up to 15.6 mA/cm 2 , and efficiencies of up to 4.25%. Using numerical device simulation, a diffusion length of about 4 μm is demonstrated for such devices. These promising results confirm that the device fabrication scheme presented in this paper is well suited for the metallization of EVA solar cells and that the electronic properties of evaporated SPC poly-Si materials are sufficient for PV applications.

Lambertian matched absorption enhancement in PECVD poly‐Si thin film on aluminum induced textured glass superstrates for solar cell applications

“…More recently, a 2.2 µm thick poly‐Si solar cell deposited on an abraded glass texture has been shown to possess excellent light trapping, with a record 29.5 mA/cm 2 short circuit current density and the 10.4% efficiency 12. We report here on our latest work with the low cost AIT process, which has been under development since 2003 by our thin film group at the University of New South Wales (UNSW) 13–17.…”

Effects of absorber doping and post-deposition treatments on the performance of n-type poly-Si thin film solar cells on glass

“…The as-deposited a-Si precursor diode then underwent solid phase crystallization (SPC), rapid thermal annealing (RTA) and hydrogen passivation. Detailed description of the post-deposition processes can be found elsewhere [3,7,8]. The design parameters of the cells are shown in Table I.…”

“…The design parameters of the cells are shown in Table I. The poly-Si cells were metalized using interdigitated Al line contacts on both the emitter and BSF layers [8]. The metalized cell structure is illustrated in Figure 1.…”

5% Efficient evaporated solid‐phase crystallised polycrystalline silicon thin‐film solar cells

“…More details on these improvements can be found elsewhere. [17][18][19] In the present paper, we concentrate on the last stage (VI) and discuss the corresponding device performance in some detail, as well as the steps that were taken to achieve this promising efficiency result.…”

“…All cells of this work were metallised using the device fabrication scheme recently developed at our Centre. 18 This metallisation scheme utilises Al line contacts located in plasma-etched grooves to contact the highly doped emitter layer. The BSF contact is also established via Al line contacts (4 lines per emitter grid line).…”