Antireflection layers are commonly used in photovoltaics to increase light absorption and therefore increase maximum photocurrent. Here, pyramid structures are created on Si surfaces with alkaline solution etching. The extent of pyramid coverage depends directly on the reaction time and as a result, the surface reflectance decreases with reaction time. A floating transfer method is used to fabricate heterojunction solar cells based on graphene oxide‐carbon nanotube and Si heterojunctions. The best device performance (photo current conversion efficiency of 13.01 ± 0.32%, which is much higher than the efficiency of the control devices (10.18 ± 0.33%)) was observed using with cells fabricated with the highest coverage (99.9%) of pyramids on the Si surfaces, which is determined to be a combined effect of reduced surface reflectance and increased effective heterojunction area per unit active area.