A Heterojunction Based on Macro-porous Silicon and Zinc Oxide for Solar Cell Application

Abstract

Transparent and conductive Al doped zinc oxide (AZO) films were reactively sputtered from metallic targets onto macro-porous silicon (MPS) substrate to fabricate a heterojunction interface structure. A tungsten oxide (WO3) thin film was placed between metallic aluminum back contact and bulk silicon to extract photogenerated holes from the absorber. Due to the susceptibility of PS to naturally oxidize over the period of time, a thin film of SiO2 was thermally grown to stabilize the electrical response of the junction. Such thin layer acts as passive film to prevent recombination and is placed between the p-n junction. Photovoltaic properties of this heterojunction were studied by using the current density-voltage (J-V) measurement under AM 1.5 illumination. The experimental results show an increase in photovoltaic performance of AZO/MPS solar cell with a buffer layers of WO3. Such heterostructures are promising for the development of the low-cost, clean, and durable devices with appreciable light-to-electricity conversion efficiency.