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我们最近报道了大剂量Al+注入原生GaN后对其光学性质的影响。表明Al+的注入可能产生了某种深能级电子陷阱 ,由于电子陷阱俘获导带电子 ,导致发光猝灭。而经一定条件的退火处理 ,可使深的电子陷阱发生变化 ,因而与缺陷间的跃迁相关的黄色荧光可得到一定程度的恢复。由于注入样品的电阻率高达 1 0 1 2 Ω·cm ,因此不能用已有的常规方法测量。我们为此发展了一种称为“光增强电流谱”(PSCS)新方法 ,用于测量高阻样品中的深能级。研究发现 ,在经过快速退火处理的样品中 ,不能消除由于注入产生的准连续深能级带 ;而在某种常规条件退火的样品中 ,发现了 5个位于导带下 1 .77eV ,1 .2 4eV ,1 .1 6eV ,0 .90eV和 0 .86eV的深电子陷阱 ,它们都是Al+注入经退火后形成的稳定结构。实验发现退火使注入产生的准连续深能级带转变为独立的深能级结构 ,虽不能使GaN的本征发光得到恢复 ,但对黄色荧光的恢复是有利的。此研究有助于了解退火处理对离子注入的GaN的电学结构与发光产生的影响。PSCS的意义在于它适用于测量一切高阻半导体样品中与非辐射跃迁相联系的深陷阱能级 ,而不仅仅适用于测量Al+注入GaN产生的深陷阱能级
We recently reported the effect of high dose Al + implantation on the optical properties of native GaN. It is suggested that some deep-level electron traps may be generated by the implantation of Al +. The emission of electrons is quenched by electron traps. Under certain conditions, the deep electron traps can be changed by the annealing process, and the yellow fluorescence associated with the transition between defects can be recovered to a certain extent. Since the injected sample has a resistivity as high as 1 0 1 2 Ω · cm, it can not be measured by existing conventional methods. To this end, we have developed a new method called “Light-Enhanced Current Spectroscopy” (PSCS) for measuring deep levels in high-impedance samples. It was found that the quasi-continuous deep level bands generated by the implantation can not be eliminated in the samples after rapid annealing. In some samples annealed under normal conditions, 5 spots located at 1.77eV, 1 under the conduction band were found. Deep electron traps of 2 4 eV, 1 .1 6 eV, 0 .90 eV, and 0 .86 eV, all of which are stable structures formed upon annealing of Al + implants. It is found that the annealing changes the quasi-continuous deep level band generated by the implantation into an independent deep level structure. Although the intrinsic emission of GaN can not be recovered, it is beneficial for the recovery of yellow fluorescence. This study helps to understand the effect of annealing on the electrical structure and luminescence of ion-implanted GaN. The significance of PSCS is that it is suitable for measuring deep-trap levels associated with non-radiative transitions in all high-resistance semiconductor samples and not only for measuring the deep-trap levels created by the implantation of Al + into GaN