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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: 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.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.


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PL spectra of InAs/GaAs QDs with and without Ga0.90In0.10As SRL.
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Fig4: PL spectra of InAs/GaAs QDs with and without Ga0.90In0.10As SRL.

Mentions: Figures 3a and b show the 2 × 2 μm AFM images of QDs with and without Ga0.90In0.10As SRL. The corresponding room temperature PL spectra are plotted in Figure 4. By inserting an Ga0.90In0.10As SRL, the InAs QD density of sample A1 is increased from 8.1 × 109 cm−2 (sample A2) to 1.2 × 1010 cm−2 (sample A1), which is consistent with the PL intensity. As is well known, the strain fields created by the QDs in the first layer strongly influence the QD nucleation on the second layer [19]. The increasing of the QD density of sample A1 with Ga0.90In0.10As SRL can be ascribed to the reduction of the accumulated strain field, which is assumed by the strain as interpreted by the XRD results. Correspondingly, the PL intensity of QDs is improved by the inserting of Ga0.90In0.10As SRL. For one reason, the QD density is increased. Secondly, less defects may be existed in sample A1 due to the decrease of lattice mismatch, leading to less SRH recombination centers [20]. These two reasons induced a better optical performance of sample A1. In addition, the PL peak of sample A1 exhibits a red shift of about 3 meV with respect to samples A2. The following reasons may need to be considered: Firstly, the relief of the compressive strain conducted a 1.94 meV red shift to the band energy, which is calculated by the following equation [21],Figure 3


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)

PL spectra of InAs/GaAs QDs 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

Fig4: PL spectra of InAs/GaAs QDs with and without Ga0.90In0.10As SRL.
Mentions: Figures 3a and b show the 2 × 2 μm AFM images of QDs with and without Ga0.90In0.10As SRL. The corresponding room temperature PL spectra are plotted in Figure 4. By inserting an Ga0.90In0.10As SRL, the InAs QD density of sample A1 is increased from 8.1 × 109 cm−2 (sample A2) to 1.2 × 1010 cm−2 (sample A1), which is consistent with the PL intensity. As is well known, the strain fields created by the QDs in the first layer strongly influence the QD nucleation on the second layer [19]. The increasing of the QD density of sample A1 with Ga0.90In0.10As SRL can be ascribed to the reduction of the accumulated strain field, which is assumed by the strain as interpreted by the XRD results. Correspondingly, the PL intensity of QDs is improved by the inserting of Ga0.90In0.10As SRL. For one reason, the QD density is increased. Secondly, less defects may be existed in sample A1 due to the decrease of lattice mismatch, leading to less SRH recombination centers [20]. These two reasons induced a better optical performance of sample A1. In addition, the PL peak of sample A1 exhibits a red shift of about 3 meV with respect to samples A2. The following reasons may need to be considered: Firstly, the relief of the compressive strain conducted a 1.94 meV red shift to the band energy, which is calculated by the following equation [21],Figure 3

Bottom Line: 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.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