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Investigation of GaInAs strain reducing layer combined with InAs quantum dots embedded in Ga(In)As subcell of triple junction GaInP/Ga(In)As/Ge solar cell.

Li S, Bi J, Li M, Yang M, Song M, Liu G, Xiong W, Li Y, Fang Y, Chen C, Lin G, Chen W, Wu C, Wang D - Nanoscale Res Lett (2015)

Bottom Line: A 1.19% improvement of the conversion efficiency was obtained via inserting the Ga0.90In0.10As strain reducing layer.The main contribution of this improvement was from the increase of the short-circuit current, which is caused by the reduction of the Shockley-Read-Hall recombination centers.Consequently, there was a decrease in open circuit voltage due to the lower thermal activation energy of confined carriers in Ga0.9In0.1As than GaAs and a reduction in the effective band gap of quantum dots.

View Article: PubMed Central - PubMed

Affiliation: Xiamen San'an Optoelectronics Co., Ltd, Xiamen, 361009 China ; Tianjin San'an Optoelectronics Co., Ltd, Tianjin, 300384 China ; Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074 China.

ABSTRACT
The InAs/GaAs quantum dots structure embedded in GaInP/Ga(In)As/Ge triple junction solar cell with and without Ga0.90In0.10As strain reducing layer was investigated. Conversion efficiency of 33.91% at 1,000 suns AM 1.5D with Ga0.90In0.10As strain reducing layer was demonstrated. A 1.19% improvement of the conversion efficiency was obtained via inserting the Ga0.90In0.10As strain reducing layer. The main contribution of this improvement was from the increase of the short-circuit current, which is caused by the reduction of the Shockley-Read-Hall recombination centers. Consequently, there was a decrease in open circuit voltage due to the lower thermal activation energy of confined carriers in Ga0.9In0.1As than GaAs and a reduction in the effective band gap of quantum dots.

No MeSH data available.


Related in: MedlinePlus

EQE of QD TJSC with and without Ga0.90In0.10As SRL.
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Fig5: EQE of QD TJSC with and without Ga0.90In0.10As SRL.

Mentions: As shown in Figure 5, the top cell in the QD TJSC with and without a Ga0.90In0.10As SRL yields EQE of 12.65 and 12.55 mA/cm2, respectively. The relative lower EQE of the top cell without Ga0.90In0.10As s SRL may be caused by the deteriorated crystalline quality of GaInP [24], which was affected by the strained InAs/GaAs QD SL in the middle cell. The EQE of the middle cell is 11.16 and 10.51 mA/cm2 in sample B1 and sample B2, respectively, and exhibits absorption edge at 950 nm. This extended absorption range is due to the QDs absorption, whose threshold wavelength is in agreement with the QD ground state transition. The spectral response of the wetting layer and QD ground state transitions is approximately 5% and approximately 1%, respectively. Remarkably, the middle cell with Ga0.90In0.10As SRL yields higher EQE response (about 75%) than that without Ga0.90In0.10As SRL (about 70%) in the spectral region below 880 nm, which can be attributed to the less defects in sample B1 and thus reduced the SRH recombination of photon generated carriers. The EQE of the bottom cell in the QD TJSC with and without Ga0.90In0.10As SRL shows an equal value at 17.2 mA/cm2 and a spectral response of approximately 73%. In comparison with top cell, the Ge bottom cell has a relative lower spectral response. Because the Ge bottom cell is indirect band gap semiconductor that has a short minority carrier diffusion lengths and short minority carrier lifetimes [25]. In a word, the short-circuit current (Isc) of the QD TJSC in this case is limited by the middle cell, suggesting that the effects of Ga0.90In0.10As SRL on current of the middle cell is significant to the final Isc of the QD TJSC.Figure 5


Investigation of GaInAs strain reducing layer combined with InAs quantum dots embedded in Ga(In)As subcell of triple junction GaInP/Ga(In)As/Ge solar cell.

Li S, Bi J, Li M, Yang M, Song M, Liu G, Xiong W, Li Y, Fang Y, Chen C, Lin G, Chen W, Wu C, Wang D - Nanoscale Res Lett (2015)

EQE of QD TJSC with and without Ga0.90In0.10As SRL.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385240&req=5

Fig5: EQE of QD TJSC with and without Ga0.90In0.10As SRL.
Mentions: As shown in Figure 5, the top cell in the QD TJSC with and without a Ga0.90In0.10As SRL yields EQE of 12.65 and 12.55 mA/cm2, respectively. The relative lower EQE of the top cell without Ga0.90In0.10As s SRL may be caused by the deteriorated crystalline quality of GaInP [24], which was affected by the strained InAs/GaAs QD SL in the middle cell. The EQE of the middle cell is 11.16 and 10.51 mA/cm2 in sample B1 and sample B2, respectively, and exhibits absorption edge at 950 nm. This extended absorption range is due to the QDs absorption, whose threshold wavelength is in agreement with the QD ground state transition. The spectral response of the wetting layer and QD ground state transitions is approximately 5% and approximately 1%, respectively. Remarkably, the middle cell with Ga0.90In0.10As SRL yields higher EQE response (about 75%) than that without Ga0.90In0.10As SRL (about 70%) in the spectral region below 880 nm, which can be attributed to the less defects in sample B1 and thus reduced the SRH recombination of photon generated carriers. The EQE of the bottom cell in the QD TJSC with and without Ga0.90In0.10As SRL shows an equal value at 17.2 mA/cm2 and a spectral response of approximately 73%. In comparison with top cell, the Ge bottom cell has a relative lower spectral response. Because the Ge bottom cell is indirect band gap semiconductor that has a short minority carrier diffusion lengths and short minority carrier lifetimes [25]. In a word, the short-circuit current (Isc) of the QD TJSC in this case is limited by the middle cell, suggesting that the effects of Ga0.90In0.10As SRL on current of the middle cell is significant to the final Isc of the QD TJSC.Figure 5

Bottom Line: A 1.19% improvement of the conversion efficiency was obtained via inserting the Ga0.90In0.10As strain reducing layer.The main contribution of this improvement was from the increase of the short-circuit current, which is caused by the reduction of the Shockley-Read-Hall recombination centers.Consequently, there was a decrease in open circuit voltage due to the lower thermal activation energy of confined carriers in Ga0.9In0.1As than GaAs and a reduction in the effective band gap of quantum dots.

View Article: PubMed Central - PubMed

Affiliation: Xiamen San'an Optoelectronics Co., Ltd, Xiamen, 361009 China ; Tianjin San'an Optoelectronics Co., Ltd, Tianjin, 300384 China ; Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074 China.

ABSTRACT
The InAs/GaAs quantum dots structure embedded in GaInP/Ga(In)As/Ge triple junction solar cell with and without Ga0.90In0.10As strain reducing layer was investigated. Conversion efficiency of 33.91% at 1,000 suns AM 1.5D with Ga0.90In0.10As strain reducing layer was demonstrated. A 1.19% improvement of the conversion efficiency was obtained via inserting the Ga0.90In0.10As strain reducing layer. The main contribution of this improvement was from the increase of the short-circuit current, which is caused by the reduction of the Shockley-Read-Hall recombination centers. Consequently, there was a decrease in open circuit voltage due to the lower thermal activation energy of confined carriers in Ga0.9In0.1As than GaAs and a reduction in the effective band gap of quantum dots.

No MeSH data available.


Related in: MedlinePlus