With a high surface-to-volume ratio, a Ga-polar GaN nanorod array was designed and obtained as a precursor for growing ferromagnetically enhanced GaN:Mn film by MOCVD. HRXRD and Raman scattering results might imply a correlation between the ferromagnetism in GaN:Mn and built-in defects in the intrinsic GaN lattice, which were produced when Mn doping was carried out.

The growth and properties of N-polar GaN layers by metal organic chemical vapor deposition (MOCVD) were reported. It is found that N-polar GaN grown on normal sapphire substrate shows hexagonal hillock surface morphology. With the misorientation angles increasing from 0.5° to 2.0° toward the a-plane of the sapphire substrate, the number of the hillock becomes less and less and finally the surface becomes flat one on the sapphire substrate with the misorientation angle of 2°. It is also found that the crystalline quality and the strain in the GaN are greatly influenced by the misorientation angle.

Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer, strong magnetic responses were observed in the magnetic force microscopy (MFM) measurement, which revealed that the films were independent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope (AFM) and MFM measurements covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN: Mn and gave a strong evidence of our GaN: Mn as the intrinsic diluted magnetic semiconductor (DMS). The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide (DMO) systems.

A detailed study is presented on magnetic, electrical and optical properties of Ga1−xMnxN: Si film grown by metal organic chemical vapor deposition (MOCVD) with high-purity SiH4 as the Si dopant source. The room-temperature field dependence magnetization and zero-field-cooled (ZFC)/field-cooled (FC) measurements indicate that the film remains room-temperature ferromagnetism and it declines slightly after Si co-doping. However, room-temperature Hall measurements indicate that the electrical property of the film improves distinctly compared with Ga1−xMnxN. Cathode luminescence (CL) measurements show an obvious enhancement in luminous property and different peak strength changes at three different positions. Therefore, we demonstrate that Fermi level and the electron structure of Mn atoms will change with variation of the impurities co-doped and the intrinsic defects and this may be related with room-temperature ferromagnetism and the other corresponding properties of the film.

In this letter, Raman spectra for a series of (Ga, Mn)N samples with different Mn concentration grown by MOCVD have been investigated. A new vibrational mode at 577 cm−1 obtained is assigned to the local vibrational mode (LVM) of Mn substituting the Ga site. Another mode at 667 cm−1 arises from vibrational mode of nitrogen vacancies-related defects. It is found that Mn doping increases the lattice disorder and other built-in defects such as the nitrogen vacancies. The room temperature ferromagnetism is not only dependent on the substitutional Mn content but also strongly related to these lattice disorder and negative defects in (Ga, Mn)N films.

In this work, InGaN/GaN multi-quantum wells (MQWs) high brightness light emitting diode (LED) was grown by metalorganic chemical deposition (MOCVD). Photoluminescence (PL), X-ray diffraction (XRD), cathodoluminescence (CL), transmission electron microscope (TEM) were performed on the LED wafers to investigate the effects of growth temperature, well width and In composition in the InGaN quantum well on the emitting wavelength of LED. It was found that the wavelength of InGaN MQW-LED shifted from about 400–470 nm due to the difference in the In composition introducing into the InGaN well layer at different growth temperature. It was also demonstrated that the wavelength can be changed from 470 nm to 504 nm only by changed the thickness of the InGaN quantum well layer. Combined with the CL image and TEM observation, it was concluded that the change from MQW structure to multi-quantum dot structure would be the cause of the shift from 470 to 504 nm by changed the InGaN well width.