Fig. 1. (Color online) Structures of (a) flat and (b) textured HIT solar cell in this study.

Fig. 2. (Color online) The fitting results of measured/calculated transmittance and reflectance curves of different layers. (a) ITO. (b) p-a-Si:H. (c) i-a-Si:H. (d) n-a-Si:H.

Fig. 3. (Color online) The calculated results of optical constants of different layers. (a) ITO. (b) p-a-Si:H. (c) i-a-Si:H. (d) n-a-Si:H.

Fig. 4. (Color online) Schematic optical model of (a) multi-layer system with all coherent layers and (b) multi-layer system with coherent and incoherent layers.

Fig. 5. (Color online) The fitting results of measured/calculated transmittance and reflectance curves on a modified c-Si thickness of 8000 nm with (a) t = 1 in Eq. (10), and (b) t = 10 in Eq. (10).

Fig. 6. (Color online) The calculation results of EQE simulation on the flat HIT solar cells. (a) The fitting results between the measured EQE and different calculated curves. (b) and (c) The EQE sensitivity on the thickness of p-a-Si:H and i-a-Si:H layers, respectively.

Fig. 7. (Color online) Optical analysis of the flat HIT solar cell. (a) Measured/calculated EQE results. (b) The contribution of each layer on the current loss (or gain) in the device.

Fig. 8. (Color online) Calculation results of flat HIT solar cell with p-a-SiO_x:H as the front doping layer. (a) EQE calculation results. (b) The contribution of each layer on the current loss (or gain) in the device.

Fig. 9. (Color online) Calculation results of flat HIT solar cell with Ag/Al electrode as rear metal layer. (a) EQE calculation results. (b) The contribution of each layer on the current loss (or gain) in the device.

Fig. 10. (Color online) Optical analysis of the textured HIT solar cell. (a) Measured/calculated EQE calculation results. (b) The contribution of each layer on the current loss (or gain) in the device.