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A novel method for crystalline silicon solar cells with low contact resistance and antireflection coating by an oxidized Mg layer.

Lee J, Lee YJ, Ju M, Ryu K, Kim B, Yi J - Nanoscale Res Lett (2012)

Bottom Line: In this paper, an evaporated Mg layer is used to reduce series resistance of c-Si solar cells.Small work function difference between Mg and n-type silicon reduces the contact resistance.It can be applied to the manufacturing of low-cost, simple, and high-efficiency solar cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746, South Korea. yi@yurim.skku.ac.kr.

ABSTRACT
One of the key issues in the solar industry is lowering dopant concentration of emitter for high-efficiency crystalline solar cells. However, it is well known that a low surface concentration of dopants results in poor contact formation between the front Ag electrode and the n-layer of Si. In this paper, an evaporated Mg layer is used to reduce series resistance of c-Si solar cells. A layer of Mg metal is deposited on a lightly doped n-type Si emitter by evaporation. Ag electrode is screen printed to collect the generated electrons. Small work function difference between Mg and n-type silicon reduces the contact resistance. During a co-firing process, Mg is oxidized, and the oxidized layer serves as an antireflection layer. The measurement of an Ag/Mg/n-Si solar cell shows that Voc, Jsc, FF, and efficiency are 602 mV, 36.9 mA/cm2, 80.1%, and 17.75%, respectively. It can be applied to the manufacturing of low-cost, simple, and high-efficiency solar cells.

No MeSH data available.


Carrier lifetimes of Si wafers with different Mg thicknesses and sintering steps. Mg200, thickness of Mg is 200 Å; Mg300, thickness of Mg is 300 Å; Mg400, thickness of Mg is 400 Å.
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Figure 3: Carrier lifetimes of Si wafers with different Mg thicknesses and sintering steps. Mg200, thickness of Mg is 200 Å; Mg300, thickness of Mg is 300 Å; Mg400, thickness of Mg is 400 Å.

Mentions: Figure 3 shows the carrier lifetimes of Si wafers with different Mg thicknesses (200 to 400 Å) and sintering steps. After the first oxidation, the lifetimes of Mg200, Mg300, and Mg400 were 13.78, 11.84, and 10.9 μs, respectively. The second oxidation does not affect the lifetime much, showing that the oxidation process at 150°C does not contribute to the oxidization of Mg. However, a sharp increase in the lifetime is seen after the last oxidation especially in the case of Mg200. The lifetimes of Mg200, Mg300, and Mg400 increase from 13.79, 11.84, and 10.95 μs to 32.27, 24.35, and 20.03 μs, respectively. When the deposited layer of the Mg metal is thin, the thickness of MgO formed after the oxidation process is also thin and does not serve as a good passivation or ARC layer. It shows that the best passivation is obtained when the thickness of the Mg metal is around 200 Å. As the amount of Mg increases, the resistance increases and the passivation deteriorates. From the results, a 200-Å thickness of Mg is required to form a desired dense MgO layer [13].


A novel method for crystalline silicon solar cells with low contact resistance and antireflection coating by an oxidized Mg layer.

Lee J, Lee YJ, Ju M, Ryu K, Kim B, Yi J - Nanoscale Res Lett (2012)

Carrier lifetimes of Si wafers with different Mg thicknesses and sintering steps. Mg200, thickness of Mg is 200 Å; Mg300, thickness of Mg is 300 Å; Mg400, thickness of Mg is 400 Å.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3275516&req=5

Figure 3: Carrier lifetimes of Si wafers with different Mg thicknesses and sintering steps. Mg200, thickness of Mg is 200 Å; Mg300, thickness of Mg is 300 Å; Mg400, thickness of Mg is 400 Å.
Mentions: Figure 3 shows the carrier lifetimes of Si wafers with different Mg thicknesses (200 to 400 Å) and sintering steps. After the first oxidation, the lifetimes of Mg200, Mg300, and Mg400 were 13.78, 11.84, and 10.9 μs, respectively. The second oxidation does not affect the lifetime much, showing that the oxidation process at 150°C does not contribute to the oxidization of Mg. However, a sharp increase in the lifetime is seen after the last oxidation especially in the case of Mg200. The lifetimes of Mg200, Mg300, and Mg400 increase from 13.79, 11.84, and 10.95 μs to 32.27, 24.35, and 20.03 μs, respectively. When the deposited layer of the Mg metal is thin, the thickness of MgO formed after the oxidation process is also thin and does not serve as a good passivation or ARC layer. It shows that the best passivation is obtained when the thickness of the Mg metal is around 200 Å. As the amount of Mg increases, the resistance increases and the passivation deteriorates. From the results, a 200-Å thickness of Mg is required to form a desired dense MgO layer [13].

Bottom Line: In this paper, an evaporated Mg layer is used to reduce series resistance of c-Si solar cells.Small work function difference between Mg and n-type silicon reduces the contact resistance.It can be applied to the manufacturing of low-cost, simple, and high-efficiency solar cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746, South Korea. yi@yurim.skku.ac.kr.

ABSTRACT
One of the key issues in the solar industry is lowering dopant concentration of emitter for high-efficiency crystalline solar cells. However, it is well known that a low surface concentration of dopants results in poor contact formation between the front Ag electrode and the n-layer of Si. In this paper, an evaporated Mg layer is used to reduce series resistance of c-Si solar cells. A layer of Mg metal is deposited on a lightly doped n-type Si emitter by evaporation. Ag electrode is screen printed to collect the generated electrons. Small work function difference between Mg and n-type silicon reduces the contact resistance. During a co-firing process, Mg is oxidized, and the oxidized layer serves as an antireflection layer. The measurement of an Ag/Mg/n-Si solar cell shows that Voc, Jsc, FF, and efficiency are 602 mV, 36.9 mA/cm2, 80.1%, and 17.75%, respectively. It can be applied to the manufacturing of low-cost, simple, and high-efficiency solar cells.

No MeSH data available.