Figure 1 Typical interconnect scheme of an α-Si:H module in superstrate configuration. P1, P2 and P3 indicate the different patterning steps. P1 is performed using an infrared laser to remove the front TCO. P2 and P3 use a green laser to cut the Si solar absorber layer and the rear electrode, respectively. In this letter, we demonstrate how the
energy density threshold for the scribing of the transparent contacts can be significantly reduced by replacing the standard thick AZO single layer with a 10 times thinner AZO/Ag/AZO multilayer structure with better electrical and optical properties. More specifically, for the lowest used pulse Quisinostat cell line energy, we measure a separation resistance for the AZO/Ag/AZO structure 8 orders of magnitude higher compared to much thicker AZO, currently used in thin film solar cells.
The experimental results and the numerical simulations provide clear Sotrastaurin nmr evidences of the key role played by the silver interlayer to steep temperature increase at the DMD/glass interface, leading to a more efficient P1 scribing through a reduction of the fluence in a single laser pulse. These results could open great opportunities for the implementation of thin AZO/Ag/AZO electrodes Ruxolitinib cell line on large-area modules liable to segmentation, such as for α-Si:H solar panels. Methods AZO/Ag/AZO multilayers were sequentially deposited on conventional soda lime glass substrates by RF magnetron sputtering at room temperature in argon atmosphere with a working pressure of 1 Pa. A ceramic AZO target containing 2 wt.% Al2O3 and a pure Ag target were employed as source materials. The sputtering powers were 225 and 30 W for AZO and Ag, respectively. The deposition times were set in order to obtain 40 nm for both top and bottom AZO films and an optimum thickness of 10 nm for the Ag interlayer. This
value was selected to fabricate a DMD structure that has high optical transparency in the visible range and good electrical conductivity [5]. The thicknesses of the films were verified by Rutherford backscattering spectrometry (RBS; 2.0-MeV He+ beam) measurements in normal detection mode. Laser treatments were performed in air by a single O-methylated flavonoid pulsed (12 ns) Nd:YAG laser operating with an infrared (λ = 1,064 nm), Gaussian-shaped (FWHM = 1 mm) beam. The laser power was varied to obtain fluences in the range from 1.15 to 4.6 J/cm2. The morphologies of the AZO/Ag/AZO multilayer after the laser irradiation process were investigated by field emission scanning electron microscopy (SEM) using a Zeiss Supra 25 microscope (Oberkochen, Germany). Electrical sheet resistance (R sh) of about 8 Ω/sq was measured on the as-deposited DMD electrode using a four-point terminal method by employing an HL5560 system (Bio-Rad, Hercules, CA, USA), while the change of the conductivity due to laser ablation process has been mapped by lateral current–voltage characteristics acquired with a Keithley 4200 semiconductor characterization system (Cleveland, OH, USA).