Three- to two-dimensional transition in electrostatic screening of point charges at semiconductor surfaces studied by scanning tunneling microscopy

Article

关键词: III-V SEMICONDUCTORS;    GAAS(110) SURFACE;    INP(110) SURFACES;    ELECTRONIC-STRUCTURE;    GAP(110) SURFACES;    ANION VACANCIES;    DOPANT ATOMS;    DEFECTS;    SPECTROSCOPY;    GAAS;   

DOI  :  10.1103/PhysRevB.80.245314

来源: SCIE

【 摘 要 】

The electrostatic screening of localized electric charges on semiconductor surfaces is investigated quantitatively by statistically analyzing the spatial distribution of thermally formed positively charged anion surface vacancies on GaAs and InP(110) surfaces. Two screening regimes are found: at low vacancy concentrations the vacancy charges are found to be three-dimensionally screened by bulk charge carriers. The corresponding screening length, which increases strongly with decreasing carrier concentration, is best described by the classical bulk screening length evaluated with a surface dielectric constant. With increasing vacancy concentration at given bulk carrier concentration, a three- to two-dimensional screening transition occurs. At high vacancy concentrations, the screening is found to be governed by charge carriers located in a two-dimensional surface vacancy defect band, which is partially filled due to the vacancy-induced surface band bending.

【 授权许可】

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