当前位置: X-MOL 学术Appl. Surf. Sci. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Femto-second transient absorption spectroscopy for probing near-surface carrier-photon dynamics in gallium nitride
Applied Surface Science ( IF 6.7 ) Pub Date : 2020-07-01 , DOI: 10.1016/j.apsusc.2020.146225
S. Chouksey , P.K. Saha , V. Pendem , T. Aggarwal , A. Udai , S. Ganguly , D. Saha

Abstract Periodicity of a crystal breaks at the surface leading to a large number of surface dangling bonds. These bonds create additional states in the bandgap of a semiconductor, which induces a static built-in electric field near the surface. This field modifies the spatial distribution of carriers. With increasing surface to volume ratio, it is indispensable to understand carrier and photon dynamics at the surface. In this work, two distinct surface conditions have been created by annealing GaN surface at high temperature in oxygen and nitrogen ambients and the characteristics are compared with a pristine GaN sample. UV–visible spectroscopy and XPS measurements are carried out to explore bandgap and surface stoichiometry under these surface conditions, which correlate with the pump–probe spectroscopy observations. Pristine GaN surface tends to get oxidized with time and behaves similarly to that of oxygen treated samples in longer time. The non-destructive femto-second pump–probe spectroscopy is employed to probe the carrier and photon evolution at the surface. The surface potential is measured by KPFM, which corroborates our observations that bands favor the accumulation of holes for some cases, while accumulation of electrons is facilitated in other cases. Photoluminescence analysis also suggest modification of the transition energy with these treatments.

中文翻译:

用于探测氮化镓中近表面载流子-光子动力学的飞秒瞬态吸收光谱

摘要 晶体在表面断裂的周期性导致大量的表面悬空键。这些键会在半导体的带隙中产生额外的状态,从而在表面附近感应出一个内置的静态电场。该字段修改了载波的空间分布。随着表面体积比的增加,了解表面的载流子和光子动力学是必不可少的。在这项工作中,通过在氧和氮环境中对 GaN 表面进行高温退火,创建了两种不同的表面条件,并将其特性与原始 GaN 样品进行了比较。进行紫外-可见光谱和 XPS 测量以探索这些表面条件下的带隙和表面化学计量,这与泵-探针光谱观察相关。原始的 GaN 表面往往会随着时间的推移而被氧化,并且在更长的时间内表现得与氧处理过的样品相似。采用非破坏性飞秒泵浦探测光谱来探测表面的载流子和光子演化。表面电位由 KPFM 测量,这证实了我们的观察,即在某些情况下,带有利于空穴的积累,而在其他情况下则促进了电子的积累。光致发光分析还表明通过这些处理改变了跃迁能。这证实了我们的观察,即在某些情况下,带有利于空穴的积累,而在其他情况下则促进了电子的积累。光致发光分析还表明通过这些处理改变了跃迁能。这证实了我们的观察,即在某些情况下,带有利于空穴的积累,而在其他情况下则促进了电子的积累。光致发光分析还表明通过这些处理改变了跃迁能。
更新日期:2020-07-01
down
wechat
bug