Deji Akinwande, University of Texas, Austin
Phosphorene and Silicene: Complexity and Opportunity in Buckled Atomic Sheets
Written by Tyler W. Farnsworth
Phosphorus, otherwise known as the “devil’s element,” was a “hot” topic during Thursday’s afternoon session of Symposium EE. Since its first discovery, phosphorus has revolutionized society through its use in explosives/fireworks (white allotrope) and its use in the striking strip of matches (red phosphorus). Another allotrope, black phosphorus, hopes to bring new discoveries in nanoelectronics with its tunable bandgap from 0.3 eV to 2 eV. Deji Akinwande spoke on his work on phosphorene, a single monolayer of the layered black phosphorus structure, as well as silicene, a new two-dimensional (2D) material comprised solely of silicon atoms. He hopes to use these materials in such applications as wearable technology and flexible electronics. With mobilities approaching 1,000 cm2/Vs and on/off ratios of 104 and 105, Akinwande argues that phosphorene just may be the best “classical” 2D material. He even played music through a phosphorene single transistor demodulator to demonstrate its utility. Despite this promise, he warns of the air instability of the material as it is known to degrade upon air exposure. However, he countered with the fact that his group (and several others) have demonstrated several methods to passivate the material and allow phosphorene to be used to its full potential. The second half of Akinwande’s talk focused on silicene, a novel 2D material. Although Akinwande briefly discussed silicene’s potential, the main focus was that silicene’s transport property is protected by its natural symmetry (topological insulator), giving it a unique advantage over other 2D materials. We can expect to hear more about these two materials as the technology continues to advance.