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Element doping is an important way to modify the properties of semiconductor materials. In our previous work, it was found that nitrogen-doping in β-Ga2O3 nanowires can induce a novel luminescence emission (around 740 nm) caused by generation of acceptor levels at the middle of the band gap of the β-Ga2O3 nanowires. Here we report that further heavy doping of nitrogen can transform the β-Ga2O3 nanowires completely into wurtzite structured GaN nanowires. Transmission electron microscopy (TEM), x-ray diffraction (XRD) and Raman spectrum are used to evaluate the transition process. Both XRD and Raman analysis reveal that the monoclinic β-Ga2O3 nanowires start phase transformation at a temperature around 850°C towards wurtzite structured GaN. Our results will be very helpful to profound our understanding of the doping induced effects and phase transformation in semiconductor compounds.

A one-dimensional random nanocrystalline chain model is established. A dc electron-phonon-field conductance model of electron tunnelling transfer is set up, and a new dc conductance formula in one-dimensional nanometre systems is derived. By calculating the dc conductivity, the relationship among the electric field, temperature and conductivity is analysed, and the effect of the crystalline grain size and the distortion of interfacial atoms on the dc conductance is discussed. The result shows that the nanometre system appears the characteristic of negative differential dependence of resistance and temperature at low temperature. The dc conductivity of nanometre systems varies with the change of electric field and trends to rise as the crystalline grain size increases and to decrease as the distorted degree of interfacial atoms increases.

In this paper, we establish a one-dimensional random nanocrystalline chain model, we derive a new formula of ac electron-phonon-field conductance for electron tunnelling transfer in one-dimensional nanometre systems. By calculating the ac conductivity, the relationship between the electric field, temperature and conductivity is analysed and the effect of crystalline grain size and distortion of interfacial atoms on the ac conductance is discussed. A characteristic of negative differential dependence of resistance and temperature in the low-temperature region for a nanometre system is found. The ac conductivity increases linearly with rising frequency of the electric field and it tends to increase as the crystalline grain size increases and to decrease as the distorted degree of interfacial atoms increases.