Enhanced and Passivated Co-doping Effect of Organic Molecule and Bromine on Graphene/HfO<sub>2</sub>/Silicon Metal–Insulator–Semiconductor (MIS) Schottky Junction Solar Cells
Kalyani D. Kadam, Malik Abdul Rehman, Honggyun Kim, Shania Rehman, Muhammad Asghar Khan, Muhammad Asghar Khan, Harshada Patil, Jamal Aziz, Sewon Park, Muhammad Abdul Basit, Karim Khan, Ayesha Khan Tareen, Muhammad Farooq Khan, Muhammad Farooq Khan, Deok‐kee Kim
Abstract
Graphene (Gr) has shown a significant role in photovoltaic applications due to its exclusive properties. In this study, we established a facile approach to fabricate p-Gr/HfO2/n-silicon, a metal–insulator–semiconductor (MIS) Schottky junction solar cell. Nevertheless, the poor work function of Gr and high-density defect states at the Gr/Si interface obstruct the efficiency of solar cells. To avoid this problem, the optimal thickness of the interfacial layer (HfO2) is employed, which circumvents the recombination process at the Gr/Si interface. Additionally, to boost the Schottky barrier height and Gr’s work function, a combination of p-type co-doping of organic molecule 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) and Br is studied. Therefore, a higher work function aims to encourage the built-in potential, which ultimately improves the open-circuit voltage and current density and deteriorates the series resistance of solar cells. Hence, a unique combination of dopants resulted in improved efficiency of up to 12.31%. Moreover, devices with double layer (MoO3/HfO2) passivation have been enabled to provide outstanding stability for over 180 days. The combined effect of p-type co-doping and double layer passivation developed a solar cell having a significant efficiency of 14.01%. Thus, this work intends to show a promising, high-performance and stable MIS Schottky junction solar cell for massive commercialization of photovoltaic devices.