Influence of the duty cycle of pulsed DC magnetron sputtering on ITO films for amorphous/crystalline silicon heterojunction solar cells

Silicon heterojunction (SHJ) solar cells were fabricated by depositing indium tin oxide (ITO) films on Si (100) and glass substrates via DC magnetron sputtering to study the influence of the duty cycle of pulsed DC power on the structural, optical and electrical properties of the ITO films. The ITO films showed a lowest resistivity of 3.55×10^-4 ω · cm and high transmittance above 85%. The local strain in the crystal lattice of the ITO films deposited with the 30% duty cycle was smaller than that of the ITO films deposited at the 20% and 40% duty cycles. Thus, the ITO films deposited at the 30% duty cycle had better charge carrier collection. The pulsed DC magnetron sputtered ITO films were employed as a front electrode for SHJ solar cells. The solar cells with ITO films deposited at the 30% duty cycle yield a maximum implied V_oc of 735.7 mV and efficiency of 20.13%. The SHJ solar cell deposited with a duty cycle of 30% also showed the lowest series resistance and the maximum quantum efficiency at lower wavelengths (380-520 nm).