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P-type GaN (p-type + gan)
Selected AbstractsOptical, structural, and magnetic properties of p-type GaN implanted with Fe+ (5 and 10 at%)PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2007Yoon Shon Abstract p-type GaN epilayers were prepared by metalorganic chemical vapor deposition and subsequently implanted with Fe+. The results of energy dispersive X-ray peak displayed the Fe-injected concentration of 5 and 10 at%, respectively. The results of photoluminescence measurement show that optical transitions related to Fe appear at 2.5 and 3.1 eV. It was confirmed that the photoluminescence peak at 2.5 eV is a donor-Fe acceptor transition and the photoluminescence peak at 3.1 eV is a conduction band-Fe acceptor transition. Apparent ferromagnetic hysteresis loops measured at 10 and 300 K with the Fe concentration of 10 at% were observed, and the temperature-dependent magnetization displayed a ferromagnetic behavior persisting up to 300 K. The systematic enhancement of ferromagnetic hysteresis loops for GaN implanted with high doses of Fe (5 , 10 at%) takes place with an increase in the annealing temperature from 700 to 850 °C. The trends of magnetic properties coincide with the results of the increased full width at half maximum of triple axis diffraction for GaN (0002) including the appearance of GaFeN, the enhanced Fe-related photoluminescence transitions, and the increased sizes of symmetric spin ferromagnetic domains GaFeN in atomic force microscopy and magnetic force microscopy systematically. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electrical transport phenomena in magnesium-doped p-type GaNPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 3 2009Leszek Konczewicz Abstract In this paper we present the resistivity and Hall-effect measurements on p-type GaN doped with Mg. The experiments were carried out as a function of hydrostatic pressure up to 1200 MPa in the temperature range 260,400 K. Both bulk GaN crystals as well as GaN:Mg epilayers were studied. In the investigated samples the decrease of resistivity and increase of hole concentration under pressure was observed. Such a behavior, which is contrary to the n-type material, strongly suggests a decrease of the ionization energy of Mg acceptor (Ea = 183 meV) with pressure. This shift is very weak, less than ,2 meV/GPa. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Comparison of deep level spectra in p-type and n-type GaN grown by molecular beam epitaxyPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2007A. Armstrong Abstract Deep levels in n-type GaN:Si and p-type GaN:Mg grown by molecular beam epitaxy were compared using deep level optical spectrscopy (DLOS). For n-GaN, the major bandgap states were observed to lie within 1 eV of the valence band edge. For the p-type film, hole photoemission from deep levels at near the conduction band edge and electron photoemission from a deep level near the valence band edge were resolved. Overall, the p-GaN filmed incorporated nearly ten times greater deep level concentration. Bandgap states attributed to residual carbon impurities with large concentration were found near the minority band edge in both films. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Oxidation treatment on Ni/Au Ohmic contacts to p-type GaNPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2003Z. Z. Chen Abstract Current,voltage (I,V) characteristics, transmission line method (TLM), and optical transmittance measurements are performed to investigate the effects of thermal oxidation and plasma-induced oxidation treatments on Ni/Au contacts to p-type GaN. Whether oxidation and thermal annealing are performed simultaneously or in succession, the specific contact resistances of Au/Ni/p-GaN are reduced. As to plasma-induced oxidation, neither no-oxidation nor long-time oxidation treatments on Ni/Au layers are suitable for obtaining a low-resistance Ohmic contact. The roles of oxidation are believed to activate the Mg acceptor in p-GaN and to form an oxygenous intermediate semiconductor layer, which may lower the Schottky barrier height between the metal layer and p-GaN. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||