We report a GaInP/GaAs tandem solar cell with a novel GaAs tunnel junction（TJ） with using tellurium（Te） and magnesium（Mg） as n- and p-type dopants via dual-filament low temperature effusion cells grown by molecu...We report a GaInP/GaAs tandem solar cell with a novel GaAs tunnel junction（TJ） with using tellurium（Te） and magnesium（Mg） as n- and p-type dopants via dual-filament low temperature effusion cells grown by molecular beam epitaxy（MBE） at low temperature. The test Te/Mg-doped GaAs TJ shows a peak current density of 21 A/cm2. The tandem solar cell by the Te/Mg TJ shows a short-circuit current density of 12 m A/cm2, but a low open-circuit voltage range of1.4 V^1.71 V under AM1.5 illumination. The secondary ion mass spectroscopy（SIMS） analysis reveals that the Te doping is unexpectedly high and its doping profile extends to the Mg doping region, thus possibly resulting in a less abrupt junction with no tunneling carriers effectively. Furthermore, the tunneling interface shifts from the intended Ga As n＋＋/p＋＋junction to the AlGaInP/GaAs junction with a higher bandgap AlGaInP tunneling layers, thereby reducing the tunneling peak. The Te concentration of ~ 2.5 × 1020 in GaAs could cause a lattice strain of 10-3 in magnitude and thus a surface roughening,which also negatively influences the subsequent growth of the top subcell and the GaAs contacting layers. The doping features of Te and Mg are discussed to understand the photovoltaic response of the studied tandem cell.展开更多
In this paper, influence of temperature and reverse bias on photocurrent spectrum and spectral response of a monolithic GalnP/GaAs double-junction solar cell was investigated in detail. Two sharp spectral response off...In this paper, influence of temperature and reverse bias on photocurrent spectrum and spectral response of a monolithic GalnP/GaAs double-junction solar cell was investigated in detail. Two sharp spectral response offsets, corresponding to the bandedge photo absorption of the bottom GaAs and the top GalnP subcells, respectively, show the starting response points of individual subcells. More interestingly, the cell photocurrent was found to enhance significantly with increasing the temperature. In addition, the cell photocurrent also increases obviously as the reverse bias voltage increases. The integrated photocurrent intensity of the top GalnP subcell was particularly addressed. A theoretical model was proposed to simulate the reverse bias dependence of the integrated photocurrent of the GalnP subceU at different temperatures.展开更多
An altemative way is proposed to interpret I-V characteristics of GalnP single-junction solar cells by position-dependent leakage ofphotocurrent. With this approach, the I-V curves of solar cells under non-uniform ill...An altemative way is proposed to interpret I-V characteristics of GalnP single-junction solar cells by position-dependent leakage ofphotocurrent. With this approach, the I-V curves of solar cells under non-uniform illumination are well analyzed. The effective spreading resistance is also extracted to understand the dynamic behavior of between the open-circuit voltage and short-circuit current points. The conditions under which the one- diode model will fail are addressed in detail. These analyses are also applicable for a characterization of the I-V curves with lateral voltage distribution under uniform illumination.展开更多
基金Project supported by the SINANO-SONY Joint Program(Grant No.Y1AAQ11001)the National Natural Science Foundation of China(Grant No.61274134)+1 种基金the USCB Start-up Program(Grant No.06105033)the International Cooperation Projects of Suzhou City,China(Grant No.SH201215)
文摘We report a GaInP/GaAs tandem solar cell with a novel GaAs tunnel junction（TJ） with using tellurium（Te） and magnesium（Mg） as n- and p-type dopants via dual-filament low temperature effusion cells grown by molecular beam epitaxy（MBE） at low temperature. The test Te/Mg-doped GaAs TJ shows a peak current density of 21 A/cm2. The tandem solar cell by the Te/Mg TJ shows a short-circuit current density of 12 m A/cm2, but a low open-circuit voltage range of1.4 V^1.71 V under AM1.5 illumination. The secondary ion mass spectroscopy（SIMS） analysis reveals that the Te doping is unexpectedly high and its doping profile extends to the Mg doping region, thus possibly resulting in a less abrupt junction with no tunneling carriers effectively. Furthermore, the tunneling interface shifts from the intended Ga As n＋＋/p＋＋junction to the AlGaInP/GaAs junction with a higher bandgap AlGaInP tunneling layers, thereby reducing the tunneling peak. The Te concentration of ~ 2.5 × 1020 in GaAs could cause a lattice strain of 10-3 in magnitude and thus a surface roughening,which also negatively influences the subsequent growth of the top subcell and the GaAs contacting layers. The doping features of Te and Mg are discussed to understand the photovoltaic response of the studied tandem cell.
基金This work was financially supported by the National Natural Science Foundation of China （Grant No. 11374247）
文摘In this paper, influence of temperature and reverse bias on photocurrent spectrum and spectral response of a monolithic GalnP/GaAs double-junction solar cell was investigated in detail. Two sharp spectral response offsets, corresponding to the bandedge photo absorption of the bottom GaAs and the top GalnP subcells, respectively, show the starting response points of individual subcells. More interestingly, the cell photocurrent was found to enhance significantly with increasing the temperature. In addition, the cell photocurrent also increases obviously as the reverse bias voltage increases. The integrated photocurrent intensity of the top GalnP subcell was particularly addressed. A theoretical model was proposed to simulate the reverse bias dependence of the integrated photocurrent of the GalnP subceU at different temperatures.
基金Project supported by the Union Innovation Projects of Jiangsu Province(No.BY2011182)CAS,the National Basic Research Program(No.2012CB619305)the National Natural Science Foundation of China(Nos.51272275,51302305,61376065)
文摘An altemative way is proposed to interpret I-V characteristics of GalnP single-junction solar cells by position-dependent leakage ofphotocurrent. With this approach, the I-V curves of solar cells under non-uniform illumination are well analyzed. The effective spreading resistance is also extracted to understand the dynamic behavior of between the open-circuit voltage and short-circuit current points. The conditions under which the one- diode model will fail are addressed in detail. These analyses are also applicable for a characterization of the I-V curves with lateral voltage distribution under uniform illumination.
