For many years III-V nitride semiconductors have been known as having outstanding optical, electronic and thermal properties. In this field aluminum nitride (AlN) stands out with the widest direct band gap among the III-V nitrides and that makes it a key component of deep-ultraviolet light emitting diodes. The high hardness value, thermal stability at high temperature, high thermal conductivity and high dielectric strength of AlN promote to use it in high-power electronics. Our main interest to deposit and use this material lies in its piezoelectric properties. Together with the high phase velocity these key properties render it extremely attractive for high-frequency acoustic wave devices. Now we move one step further by exploiting these properties in combination with nanocrystalline diamond layers for devices, such as SAW, BAW and µ-cantilevers, in order to boost their performance.
In the same class of materials, boron nitride is currently considered a novel semiconductor that has not yet reached its full potential. Generally, it is best known in its cubic form showing extreme material properties rivaling those of diamond. Examples are the material hardness, only second to diamond, a low chemical reactivity, and a large band gap. However, similar to carbon, BN also has sp2-bonded form, i.e. hexagonal or h-BN. This form shows similar physical properties analogous to graphene, such as high chemical and thermal stability. Our interest lies in the opto-electronic properties of this material that has been shown to be a promising candidate for a wide range of applications, including UV light emission devices. Moreover, the importance of 2D nanomaterials such as h-BN nanoribbons or nanowalls resides in different applications such as supports for functional nanoparticles, electron field emitters and gas storage.