Ammonothermal synthesis of GaN doped with transition metal ions (Mn, Fe, Cr)

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• 作者：M. Zają ; c ; J. Gosk ; E. Grzanka ; S. Stelmakh ; M. Palczewska ; A. Wysmoł ; ek ; K. Korona ; M. Kamiń ; ska ; A. Twardowski
• 关键词：Semiconductors ; Crystal growth ; Magnetization ; Optical properties ; Luminescence
• 刊名：Journal of Alloys and Compounds
• 出版年：2008
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：29 May 2008
• 卷：456
• 期：1-2
• 页码：324-338
• 文件大小：687 K

摘要

The ammonothermal technique was used to obtain GaN powders doped with various transition metal ions—Mn, Fe, Cr. The procedure of ammonothermal growth and morphology, structural, magnetic and optical investigations of magnetic GaN is described. The largest solubility limit (x < 1%) was obtained in the case of Mn doping while the solubility of Fe and Cr occurred to be much smaller (0.03%and below 0.02%, respectively). Adding Mn into the growth zone reduces the crystallite size from 2–5 μm of pure GaN to even tens of nanometers depending on Mn amount added. Detected Mn²⁺ centers are responsible for the paramagnetic behavior of GaMnN. X-ray diffraction study of GaMnN revealed presence of different Mn_xN_y compounds, in particular ferromagnetic Mn₄N which may be the source of additional ferromagnetic contribution. The results show substantial difficulties to obtain hole induced ferromagnetism in GaMnN. Mn reduces the luminescence efficiency of ammonothermal GaN. In the case of Fe doping we are dealing with a spectrum of different Fe centers. Ammonothermal GaN:Cr is ferromagnetic but its origin is unrecognized yet.