Zhu Mei-Fang

Effect of chemical polish etching and post annealing on the performance of silicon heterojunction solar cells

Amorphous/crystalline silicon heterostructure solar cells have been fabricated by hot wire chemical vapor deposition (HWCVD) on textured p-type substrates. The influence of chemical polish (CP) etching and the post annealing process on the solar cell performance have been studied. The CP treatment leads to a reduction of stress in the i-layer by the slight rounding of the pyramid peaks, therefore improving the deposition coverage and the contact by each layer, which is beneficial for the performance of the solar cells. An optimized etching time of 10–15 s has been obtained. A post annealing process leads to a considerably improved open voltage (Voc), filled factor (FF), and conversion efficiency (η) by restructuring the deposited film and reducing the series resistance. An efficiency of 15.14% is achieved that represents the highest result reported in China for an amorphous/crystalline heterostructure solar cells based on the textured p-type substrates.

Fabrication of c-Si:H(p)/c-Si(n) Heterojunction Solar Cells with Microcrystalline Emitters

The p-type microcrystalline silicon (μc-Si:H) on n-type crystalline silicon (c-Si) heterojunction solar cells is fabricated by radio-frequency plasma enhanced chemical vapour deposition (rf-PECVD). The effect of the μc-Si:H p-layers on the performance of the heterojunction solar cells is investigated. Optimum μc-Si:H p-layer is obtained with hydrogen dilution ratio of 99.65%, rf-power of 0.08 W/cm2, gas phase doping ratio of 0.125%, and the p-layer thickness of 15 nm. We fabricate μc-Si:H(p)/c-Si(n) heterojunction solar cells without texturing and obtained an efficiency of 13.4%. The comparisons of the solar-cell performances using different surface passivation techniques are discussed.

Green/Blue Photoluminescence from Nanocrystalline Si Thin Films by Rapid Thermal Processing

The green/blue photoluminescence with peaks centered around 2.4 eV at room temperature was observed from nanocrystalline Si thin films prepared by the three-step rapid thermal annealing of hydrogenated amorphous silicon films. The effect of the parameters of rapid thermal annealing on the light emission was studied. A comparison of photoluminescence feature between the films from the rapid thermal annealing and the furnace annealing of a-Si:H has been carried out.