Unlike its cousin, graphene, silicene remains a difficult material to study experimentally. Most syntheses have been performed on noble metal surfaces under UHV conditions. Predicted by Takeda and Shiraishi in 1994, silicene did not receive widespread attention until roughly 10 years later.
Most of what is known about silicene today derives from theoretical studies. I recommend the recent review by Lew Yan Voon, Zhu, and Schwingenschlögl.