Kumar Praveen, Bhattacharya S, Mehta B R, Shivaprasad S M
Surface Physics and Nanostructure Group, National Physical Laboratory, New Delhi 110016, India.
J Nanosci Nanotechnol. 2009 Sep;9(9):5659-63. doi: 10.1166/jnn.2009.1183.
This study demonstrates the formation of two-dimensional GaN on GaAs (001) surface by bombardment of nitrogen ions at room temperature. In this work the ion induced nitridation of GaAs (001) surface using nitrogen ion beam of different energies (range from 250 eV to 5 keV) has been investigated using in-situ X-ray Photoelectron Spectroscopy (XPS). A Ga rich surface produced by Art ion etching, promotes initial nitridation. Using nitrogen ion of different energies of constant fluence performs the nitridation. The nitridation suggests that the degree of nitridation increase as the nitrogen ion energy increases up to 3 keV and then attains saturation. The core level and valance band spectra were monitored to observe the chemical and electronic changes as a function of nitrogen ion beam energy. It is observed that Ga(3d) core level peak shifts during nitridation and N(1s) core level spectra shows that the intensity of the nitrogen peak increases and the Ga (LMM) auger peak shifts towards the higher binding energy, reveal the forming of N bonds with Ga by replacing the Ga-As bonds, forming GaN.
本研究表明，在室温下通过氮离子轰击可在GaAs（001）表面形成二维GaN。在这项工作中，使用原位X射线光电子能谱（XPS）研究了使用不同能量（范围从250 eV到5 keV）的氮离子束对GaAs（001）表面进行离子诱导氮化的情况。氩离子蚀刻产生的富Ga表面促进了初始氮化。使用恒定注量的不同能量的氮离子进行氮化。氮化表明，氮化程度随着氮离子能量增加到3 keV而增加，然后达到饱和。监测了芯能级和价带光谱，以观察作为氮离子束能量函数的化学和电子变化。观察到在氮化过程中Ga（3d）芯能级峰发生位移，N（1s）芯能级光谱表明氮峰强度增加，Ga（LMM）俄歇峰向更高结合能位移，揭示了通过取代Ga-As键与Ga形成N键，从而形成GaN。
