Hydrogenated amorphous silicon film as intrinsic passivation layer deposited at various temperatures using RF remote-PECVD technique

Lee

Progress in Photovoltaics

et al. 2019

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.

Section: Introductionmentioning

confidence: 99%

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

Lee

Progress in Photovoltaics

et al. 2019

International Journal of Photoenergy

“…Interestingly, this released photon is detected by OES only in the plasma for the low-H cell, while this peak vanishes for the high-H cell. Thus, the plasma in low-H i-layer deposition contains a much larger amount of SiH 2 , finally leading to void-rich and low-quality i-layer [26,27]. In addition, another effect accompanied with high SiH 2 amount is the increased generation rate of poly silane (gas particle formation), Si 2 H 6 , according to [28] SiH 2 + SiH 4 → Si 2 H 6 (7)…”

Section: Resultsmentioning

confidence: 99%

Effect of Hydrogen Content in Intrinsic a-Si:H on Performances of Heterojunction Solar Cells

Cho

Hsu

Lien

et al. 2013

Influences of hydrogen content in intrinsic hydrogenated amorphous silicon (i-a-Si:H) on performances of heterojunction (HJ) solar cells are investigated. The simulation result shows that in the range of 0–18% of the i-layer hydrogen content, solar cells with higher i-layer hydrogen content can have higher degree of dangling bond passivation on single crystalline silicon (c-Si) surface. In addition, the experimental result shows that HJ solar cells with a low hydrogen content have a poor a-Si:H/c-Si interface. The deteriorate interface is assumed to be attributed to (i) voids created by insufficiently passivated c-Si surface dangling bonds, (ii) voids formed by SiH2clusters, and (iii) Si particles caused by gas phase particle formation in silane plasma. The proposed assumption is well supported and explained from the plasma point of view using optical emission spectroscopy.

International Journal of Photoenergy

“…At the same time, the intensity of the doublet reduces, indicating a better network structure at elevated temperature. On the other hand, reduces in a linear manner, indicating a better a-SiO :H(i) network with less H clusters and microvoids [42,61]. The combination of a high H due to slow H depletion and an improved amorphous network results in an excellent passivation quality within the process window observed in Figure 7.…”

Section: Bonding Configurationmentioning

confidence: 96%

“…The initial increase of lifetime is due to better bonding structure benefited from thermal relaxation [42,61]. Higher temperature releases incorporated H atoms from trapped state (Si-H 2 ), which is reflected by a reducing (see Figure 9).…”

Section: Passivation Qualitymentioning

confidence: 99%

Excellent Silicon Surface Passivation Achieved by Industrial Inductively Coupled Plasma Deposited Hydrogenated Intrinsic Amorphous Silicon Suboxide

Tang

Wong

et al. 2014

We present an alternative method of depositing a high-quality passivation film for heterojunction silicon wafer solar cells, in this paper. The deposition of hydrogenated intrinsic amorphous silicon suboxide is accomplished by decomposing hydrogen, silane, and carbon dioxide in an industrial remote inductively coupled plasma platform. Through the investigation on CO 2 partial pressure and process temperature, excellent surface passivation quality and optical properties are achieved. It is found that the hydrogen content in the film is much higher than what is commonly reported in intrinsic amorphous silicon due to oxygen incorporation. The observed slow depletion of hydrogen with increasing temperature greatly enhances its process window as well. The effective lifetime of symmetrically passivated samples under the optimal condition exceeds 4.7 ms on planar -type Czochralski silicon wafers with a resistivity of 1 Ωcm, which is equivalent to an effective surface recombination velocity of less than 1.7 cms −1 and an implied open-circuit voltage ( oc ) of 741 mV. A comparison with several high quality passivation schemes for solar cells reveals that the developed inductively coupled plasma deposited films show excellent passivation quality. The excellent optical property and resistance to degradation make it an excellent substitute for industrial heterojunction silicon solar cell production.