Issue 48/2015 - Black phosphorus expected to become the "second graphene"

The Shenzhen Peacock Innovation Team, led by Professor Zhang Han of the Collaborative Innovation Center for Optoelectronics of Shenzhen University-National University of Singapore, developed a fiber mode-locked laser based on black phosphorus for the first time, and obtained the output signal
of ultrashort pulse laser.

In recent years, when the graphene industry is booming, another new single-element two-dimensional atomic crystal material, black phosphorus, has been discovered
.
Similar to graphene, black phosphorus has many excellent properties, so it is called a "dream material"
comparable to graphene.
The research and application of black phosphorus has just begun, and its nonlinear optical properties have been confirmed by many at home and abroad and applied to the
generation of ultrafast lasers.
It is foreseeable that in the near future, it will become the "second graphene"
.

In May 2015, Zhang Han's team found that black phosphorus has broadband saturable light absorption characteristics, covering the wavelength range from visible light to mid-infrared wavelengths
.
In the laser field, devices with saturable absorption characteristics are the key to the
formation of ultrashort pulse lasers.
The discovery of this characteristic of black phosphorus provides the possibility
for the development of mid-infrared ultrafast optics.
Studies have shown that graphene is a bandgap semimetallic semiconductor material with ultra-high electron mobility and broadband light absorption characteristics
.
However, the band structure without band gap limits the application and development
of graphene in the field of optoelectronics.
The biggest feature of black phosphorus is that it has a direct band gap that varies with the number of layers, which just solves the problem
that plagues graphene.
(Section)