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
High quality (AlGa)InP epilayers lattice matched on GaAs substrates were grown by atmospheric pressure metallorganic vapor phase epitaxy (AP-MOVPE).The relationship between surface morphologies and lattice mismatches ...High quality (AlGa)InP epilayers lattice matched on GaAs substrates were grown by atmospheric pressure metallorganic vapor phase epitaxy (AP-MOVPE).The relationship between surface morphologies and lattice mismatches was studied.The influence of Al incorporation to the photoluminescence and electronic properties of AlGaInP was measured.The applicability of growth at atmospheric pressure and the passivation of Zn in AlGaInP were discussed.展开更多
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
An accurate and broad-band method for hetero-junction bipolar transistors(HBT) small-signal model parameters-extraction is presented in this paper. An equivalent circuit forthe HBT under a forward-bias condition is pr...An accurate and broad-band method for hetero-junction bipolar transistors(HBT) small-signal model parameters-extraction is presented in this paper. An equivalent circuit forthe HBT under a forward-bias condition is proposed for extraction of accessresistance and parasiticinductance. This method differs from previous ones by extracting the c-quivalent circuit parameterswithout using special test structure or global numerical optimization techniques. The mainadvantage of this method is that a unique and physically meaningful set of intrinsic parameters isextracted from impedance and admittance representation of the measured S-pa-rameters in thefrequency range of 1-12 GHz under different bias conditions. The method yields a deviation of lessthan 5% between measured and modeled S-parameters.展开更多
650 nm AlGaInP/GaInP laser diodes with compressively strained MQW active layer have been successfully fabricated by means of single epitaxy growth.The threshold current is 6.4 mA,at 40 mA CW operation,the fundamental ...650 nm AlGaInP/GaInP laser diodes with compressively strained MQW active layer have been successfully fabricated by means of single epitaxy growth.The threshold current is 6.4 mA,at 40 mA CW operation,the fundamental transverse-mode still remains,and the output power and the slope efficiency can reach 34 mW and 1.1 mW/mA respectively.The dead output power in CW operation can reach 66 mW at a saturation current of 88 mA.During 200 h burn in test,the laser diodes show good stabilization with a degradation of less than 8%.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.
文摘High quality (AlGa)InP epilayers lattice matched on GaAs substrates were grown by atmospheric pressure metallorganic vapor phase epitaxy (AP-MOVPE).The relationship between surface morphologies and lattice mismatches was studied.The influence of Al incorporation to the photoluminescence and electronic properties of AlGaInP was measured.The applicability of growth at atmospheric pressure and the passivation of Zn in AlGaInP were discussed.
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Supported by the National Natural Science Foun dation of China(60444004) and the AM Foundation of Shanghai Mu nicipal Science and Technology Commission of China (0109)
文摘An accurate and broad-band method for hetero-junction bipolar transistors(HBT) small-signal model parameters-extraction is presented in this paper. An equivalent circuit forthe HBT under a forward-bias condition is proposed for extraction of accessresistance and parasiticinductance. This method differs from previous ones by extracting the c-quivalent circuit parameterswithout using special test structure or global numerical optimization techniques. The mainadvantage of this method is that a unique and physically meaningful set of intrinsic parameters isextracted from impedance and admittance representation of the measured S-pa-rameters in thefrequency range of 1-12 GHz under different bias conditions. The method yields a deviation of lessthan 5% between measured and modeled S-parameters.
文摘650 nm AlGaInP/GaInP laser diodes with compressively strained MQW active layer have been successfully fabricated by means of single epitaxy growth.The threshold current is 6.4 mA,at 40 mA CW operation,the fundamental transverse-mode still remains,and the output power and the slope efficiency can reach 34 mW and 1.1 mW/mA respectively.The dead output power in CW operation can reach 66 mW at a saturation current of 88 mA.During 200 h burn in test,the laser diodes show good stabilization with a degradation of less than 8%.
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.
