In this paper, we present a study of the effect of temperature on the two-dimensional electron mobility, Hall scattering factor, and sheet conductivity, using a fully numerical calculation in unintentionally doped AlxGa1−xN/AlN/GaN heterostructures. The analysis of our results clearly indicates that the effect of partial sub-band occupancy is considerable, especially at higher operating temperatures when more than one sub-band is occupied. The comparison of our calculated results with published experimental data is shown to be in good agreement.

Raman scattering studies reveal the remarkable structure and the unusual electronic and phonon properties of carbon nanotubes. In this study, we directly produced boron, B, and nitrogen doped carbon nanotubes by using DC-arc discharge method which normally can be employed for producing carbon nanotubes. We performed experiments without using catalysts and in the presence of Ar gas for producing boron doped carbon nanotubes. At the second and third stages and in the presence of Al 2 O 3 and MgO nanopowders as catalysts and nitrogen gas were used for producing nitrogen doped carbon nanotubes. In general, our investigation revealed that some major changes caused by B and N dopants can be observed in the related recorded Raman spectra.

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