ZhongQuan Ma

A new approach for measuring P-N junction depth of textured silicon solar cells

Its difficult to measure junction depth because the junction is not in horizontal direction in textured silicon solar cells. In this paper a new, accurate junction depth measurement technique for textured silicon solar cells is investigated. Both experience and experimental data indicate that the measurement technique we used is feasible.

Influence of cooling on the performance of Silicon solar cells

Cooling was a very effective way to eliminate the bow of Silicon solar cell. In this paper, by a series of experiments, we found that during the cooling, the electrical characteristics and internal or external quantum efficiency nearly stayed the same, and the lifetime of minority carriers as well. The cooling was a available way to apply in industrial process.

Comparative Study on the Optical Band Edge of ZnO Films with Different Measurement Techniques

ZnO films were prepared by radio frequency (rf) magnetron sputtering. The absorption coefficients as a function of incident photon energy were obtained by means of spectroscopic ellipsometer (SE), as well as by using transmission and reflection measurement (T&R). The optical absorption band gap decided by SE is 3.32 eV, while that decided by T&R is 3.26 eV. The difference is ascribed to the fact that SE probes only the surface of films whereas the T&R measurement probes the bulk of the films. The same fact can also be used to explain that, at optical band edge region, the absorption coefficient decided by SE is lower than that decided by T&R. When the incident photon energy is larger than the optical band gap, exitonic transitions in the bulk of the films are used to discuss the change of the absorption coefficient vs. incident photon energy.

Fabrication and opto-electric properties of silicon based heterojunction SIS cells

ITO/AZO double films were deposited by RF sputtering on p-Si texturized substrate to fabricate ITO/AZO/SiO2/p-Si SIS heterojunction. The structural, optics and electrical properties of the ITO/AZO films were characterized by UV-VIS spectrophotometer, four point probe, respectively. The results show that ITO/AZO films have good quality. The electrical junction properties were investigated by I–V measurement, which reveals that the heterojunction shows typical good rectifying behavior and great photoelectric effect.

Affirmation of minority carrier lifetime during industrial process of crystalline silicon solar cell by microwave phtonconductance decay method

Minority carrier lifetime was determined by MW-PCD method following the industry process well and truly. The wafer as-cut without any treatment showed an effective lifetime about 1.2μs. Then it rose to 2.5∼5μs after one side was passivated by silicon nitride. The average lifetime with double layer passivation sharply increased to 48µs average, even over 100μs locally. The escape of hydrogen was discovered after sintering. The electron collection ability between Ag and Al was also compared by effective lifetime testing.

Fabrication and photoelectrical properties of AZO/SiO2/p-Si heterojunction

ZnO thin films doped with aluminum (AZO) were deposited on silicon dioxide covered p-Si (100) substrates by radio frequency magnetron sputtering, to fabricate AZO/SiO2/p-Si heterojunction, as an absorber for ultraviolet cell. The optical and electrical properties of the Al doped - ZnO films were characterized by UV-VIS spectrophotometer, current-voltage measurement, and four point probe technique, respectively. The results show that AZO films have good quality. The electrical junction properties were investigated by I-V measurement, which reveals that the heterojunction shows typical rectifying behavior.