Black phosphorous is a promising semiconductor with a number of features which make it suitable for nanoelectronics and biomedical applications. It exhibits anisotropic in-plane properties that have opened up new opportunities for photonic devices and electronic devices.
Black P is a single-elemental layered crystalline material with a simple cubic crystal structure. It consists of phosphorus atoms and a number of oxygen atoms. The band gap of thin film black P ranges from 0.3 eV to 2 eV.
Black P is stable at ordinary and high temperatures. However, it is unstable in the presence of oxygen. To isolate a few-layer black P from oxygen, micromechanical exfoliation can be used. This method yields a thickness of 4.9+-1.6 nm.
BP has excellent biocompatibility and a good biodegradability in the human body. As a result, BP is a potential material for a variety of applications, including drug delivery and cancer therapy. In fact, it has been demonstrated that BP has a higher sensitivity to target analytes than graphene.
Black P is particularly well suited for optoelectronic applications. It can be combined with other 2D materials to create hybrid structures. For instance, a black PxAs(1-x) alloy has band gaps below 0.3 eV. It can be used for chemical and thermal imaging.
Black P also demonstrates a high carrier mobility and has strong in-plane anisotropy. Unlike other 2D materials, BP is more sensitive to negatively charged biomolecules. It has a ambipolar symmetry which makes it possible to apply in biosensing. Moreover, its phonon many-body effects are novel and will play an important role in future studies.