The alloy GaN(x) As(1-x) (with x typically less than 0.05) is a novel semiconductor that has many interesting electronic properties because of the nitrogen-induced dramatic modifications of the conduction band structure of the host material (GaAs). Here we demonstrate the existence of an entirely new effect in the GaN(x) As(1-x) alloy system in which the Si donor in the substitututional Ga site...

The growth of Eu-doped GaN (GaN:Eu) films has been performed on GaAs (100) substrates using RF magnetron sputtering method. The GaN layers exhibit a wurtzite structure. Substrate temperature and the pressure during the deposition do not influence the orientation of GaN:Eu films. After annealing of GaN films in NH3, a strong red luminescence at 622 nm due to Eu ions has been observed.

We investigated the contact properties of metal/n-GaN and metal/GaOx/n-GaN in terms Fermi level pinning (FLP) by metal-induced disorder-induced gap states (MIGS DIGS). The work function ten different metals spanned a wide range from 4.2 to 5.7 eV. measured Schottky barrier height vs metal showed linear relationship with slope parameter S = 0.26 ± 0.01 for doped undoped GaN, indicating strong FL...

In this work we investigate the synthesis of Bragg reflectors consisting either of AlN/GaN or of (Al,In)N/GaN by plasma-assisted molecular beam epitaxy (MBE). In addition, we study the impact of Si-doping on the surface morphology and the structural and electrical properties of AlN/GaN Bragg reflectors in order investigate the feasibility of obtaining vertically conducting Bragg mirrors. The st...

In this paper, we address two different aspects relevant to the growth of GaN. The first part concerns alternative nitrogen source whereas in the second part, we report experimental results on Mg doping. Several nitrogen precursors have been used for the growth of GaN in MOVPE. To produce active species from N2 or NH3, a remote Plasma Enhanced Chemical Vapour Deposition (RPECVD) process has bee...

The atomic and electronic structure of hydrogen-vacancy complexes in GaN is investigated with pseudopotential-density-functional calculations. Calculated formation energies provide information about the likelihood of incorporation of these complexes in n-type and p-type material, and binding energies provide a measure for the dissociation energy. Vibrational frequencies yield a signature of the...

This paper presents experimental analysis and results of GaN (being a III-V semiconductor) doped with Ferrite elements synthesized using Sol-Gel technique which are carried out at National Chemical Laboratory, Pune Maharashtra. The GaN is employed as dopant for x=1 and x=5, in the formula Ga(2x) N Fe2(49-x) O3 . A non-spinel ferrite system ( Fe2 O3) is chosen for our study. The XRD (Structural)...

OF DOCTORAL DISSERTATION HELSINKI UNIVERSITY OF TECHNLOGY P.O. BOX 1000, FI-02015 TKK http://www.tkk.fi Author Heikki Holmberg Name of the dissertation Spin-dependent transport in Mn Doped GaAs and GaN diodes Manuscript submitted 16.11.2007 Manuscript revised 4.2.2008 Date of the defence 14.3.2008 Monograph Article dissertation (summary + original articles) Faculty Faculty of Electronics, Commu...

We report a study of the 2.8 eV blue luminescence ~BL! in heavily Mg-doped p-GaN via resonant excitation with a tunable blue dye laser. The dependence of the BL on the excitation photon energy (Eex) is unlike that of the yellow luminescence found in n-type GaN. An Urbach-type band tail, with Urbach parameter of 33 meV is observed in the vicinity of the BL energy. We propose that the peak energy...