Tunnel oxide passivating electron contacts for high‐efficiency n‐type silicon solar cells with amorphous silicon passivating hole contacts

Abstract

This study proposes a hybrid solar cell structure for a highly efficient silicon solar cell obtained by combining two passivating contact structures, namely, a heterojunction and polysilicon passivating contact. Given that the major cause of the loss in efficiency of crystalline silicon solar cells is carrier recombination at the metal‐semiconductor junction, a passivating contact having high‐quality passivation and a low contact resistance was introduced. In this study, two major passivating contact solar cells were combined. By applying an intrinsic thin amorphous silicon layer at the front and a tunneling oxide at the rear, a hybrid silicon solar cell with an efficiency of 21.8% was fabricated. Moreover, to evaluate the potential efficiency limit and to suggest methods for improving the cell performance of the proposed amorphous silicon emitter tunnel oxide back contact structure, the cell efficiency was simulated, and the result indicated that an efficiency of 26% could be achieved by controlling the thickness and resistivity of the wafer.

The role of heterointerfaces and subgap energy states on transport mechanisms in silicon heterojunction solar cells

“…Silicon heterojunction (SHJ) solar cells combine crystalline silicon (c-Si) as bulk absorber with thin-film silicon technology as transport stacks for high efficiency based on carrier-selective contacts (CSC). SHJ contact stack typically consists of hydrogenated intrinsic amorphous silicon (i-a-Si:H) layer followed by a doped thin-film silicon [1][2][3][4] (eventually alloyed with oxygen [5][6][7][8][9][10][11][12][13][14] or carbon [15][16][17] ) and a transparent conductive oxide (TCO). The purpose of these layers is to provide the so-called contact selectivity by inducing an electric potential inside the c-Si for carrier separation that allows the collection of one type of carriers while repelling the other.…”

Historical Analysis of High‐Efficiency, Large‐Area Solar Cells: Toward Upscaling of Perovskite Solar Cells

“…With each development target, various types of silicon cells have been developed. Examples include the back surface field (BSF), passivated emitter rear cell (PERC), passivated emitter rear locally diffused (PERL), passivated emitter rear totally diffused (PERT), [ 175,176 ] heterojunction with intrinsic thin layer (HIT), [ 177 ] interdigitated back contact (IBC), tunnel‐oxide passivated contact (TOPCon), [ 178–181 ] heterojunction back contact (HBC), [ 182 ] polysilicon on oxide (POLO), [ 183 ] and bifacial cell. [ 184 ]…”

Monolithic Perovskite-Carrier Selective Contact Silicon Tandem Solar Cells Using Molybdenum Oxide as a Hole Selective Layer

“…After depositing intrinsic polysilicon on the chemical tunnel oxide passivated n-type silicon wafer, phosphorus doping was performed in a tube furnace at temperatures in the range of 875-1000 • C using POCl 3 as the source. Implied Voc values were measured after an additional hydrogenation process, which can largely enhance the passivation quality of the TOPCon structure [40]. The lowest value of recombination current density was obtained after phosphorus diffusion at 925 • C, with the time varying from 5 to 25 min, as shown in Figure 3b, and a maximum implied Voc of 730.6 mV was obtained after 10 min diffusion at 925 • C. These high properties of the rear passivated contact structure improve the qualities of the entire bottom cell, even if the front MoO x passivation property is quite low.…”