Search

GaN1−xPx ternary alloys with high P compositions were deposited on sapphire substrates by means of metal-organic chemical vapor deposition. Depth profiles of the elements indicate that the maximum P/N composition ratio is about 17% and a uniform distribution of the P atoms in the alloys is achieved. 2θ/ω XRD spectra demonstrate that the (0 0 0 2) peak of the GaN1−xPx alloys shifts to smaller angle with increasing P composition. From the photoluminescence (PL) spectra, the red shifts to the bandedge emission of GaN are determined to be 73, 78, 100 and 87 meV for the GaN1−xPx alloys with the P/N composition ratios of 3%, 11%, 15% and 17%, respectively. No PL peak related to GaP is observed, indicating that the phase separation between GaN and GaP is well suppressed in our GaN1−xPx samples. [Copyright &y& Elsevier]

Raman scattering from an AlGaN/GaN heterostructure was performed in the temperature range from 77 to 773 K. The first- and second-order Raman scattering of the A1 longitudinal-optical phonon-plasmon coupled mode from an AlGaN/GaN interface as well as the Raman scattering from the GaN layer were observed. All the modes downshift, and their intensities weaken with increasing temperature. The free-carrier concentration estimated by the frequency of the coupled mode from an AlGaN/GaN interface is 7.5 times as high as that of n-AlGaN, indicating mass free-carrier transfer from the AlGaN barrier to the GaN well. Moreover, the temperature dependence of the phonon frequency is well described by an empirical formula. [ABSTRACT FROM AUTHOR]

Comments on J.K. Lao and colleagues' article 'Piezoelectric Effect on AlInGaN/GaN Heterostructures.' Effect of a small fraction of In atoms in AlInGaN/GaN on the piezoelectric field at the interface; Schematic illustration of the band structure in the triangular potential quantum well; Origin of the beating oscillations; Zero-magnetic-field spin splitting.

Abstract: IIIV x N1−x ternary alloys are promising materials for their applications in light-emitting devices in the range of wavelength from ultra violet to the infrared ray due to the large bowing of band gap energy. In this paper, molecular dynamical method was used to calculate the solubility of phosphorus in GaN by using the Gibbs free energy and the dielectric theory. The calculation results show that the content of P in GaN varies with the growth temperature, which may be larger than 25% in the N-rich GaP x N1−x or less than 90% in the P-rich GaP x N1−x , at the growth temperature of about 1500K. We compared our theoretical results with those reported in references. By using light-radiation heating together with low-pressure metal-organic chemical vapor deposition, and ion implantation techniques, we have successfully synthesized N-rich (x <0.17) and P-rich GaP x N1−x (x >0.90) compounds. [Copyright &y& Elsevier]