Optical Properties of Ordered As Layers on InP(110) Surfaces

Abstract

The structure of arsenic monolayers on InP(110) surfaces has been investigated by combining optical spectroscopy with calculations of the surface atomic structure and optical properties. A highly ordered surface structure is obtained after As deposition at room temperature followed by annealing at 300 ± C. From the excellent agreement between the experimental and theoretical results we conclude that the ordered structure consists of an InAs monolayer on the substrate surface. [S0031-9007(96)00686-2] PACS numbers: 78.66.Fd, 68.35.Md, 78.30.Fs The adsorption of group-V overlayers on III-V (110) surfaces is of large interest for fundamental studies of interface formation. Among those, much work has been dedicated to the study of Sb monolayers on III-V (110) surfaces which are known to form an exceptionally well-defined, atomically abrupt and ordered ͑1 3 1͒ overlayer [1]. This prototype system for surface studies has been thoroughly investigated by means of optical spectroscopic techniques such as reflectance difference spectroscopy (RDS), spectroscopic ellipsometry (SE), and surface resonant Raman spectroscopy [2][3][4]. The studies have demonstrated the large potential of optical techniques for surface analysis and, moreover, gave insight into the microscopic origin of the surface optical properties by comparison with theoretical work. In contrast, much less is known about the interaction of As with III-V (110) surfaces. Arsenic adsorbates on GaAs(100) surfaces have been studied in the past by optical methods because of their role in the epitaxial growth process [5]. However, studies of As on InP(110) surfaces have been restricted to low-energy electron diffraction (LEED) and photoemission investigations by Tulke and Lüth [6] and Chassé, Neuhold, and Horn [7], and theoretical calculations of their atomic structure are not available.The question to be addressed here is whether As remains on the substrate surface forming well-defined surface monolayers, as in the case of antimony and bismuth terminated III-V surfaces [8][9][10][11], or whether a significant chemical reaction with the substrate top layers occurs, such as observed for the (100) InP surface [12]. For this purpose we present an investigation of arsenic monolayers on InP(110) surfaces (hereafter InP:As) combining a spectroscopic study of the surface optical properties with microscopic calculations of the atomic structure and optical spectra. In agreement with Refs.[6] and [7] we detected a poorly ordered InP:As phase (phase A), obtained after As deposition at room temperature (RT) and a highly ordered phase (phase B) with coverage in the monolayer range, formed after annealing at temperatures above 300 ± C. One can reversibly go from one phase to the other by changing the As coverage by either thermal desorption ͑A ! B͒ or As deposition ͑B ! A͒. The structure of the ordered phase B was further investigated by performing ab initio total energy calculations of the ground state geometries and of the optical properties for different surface configurations...

Probing the out-of-plane optical response of plasmonic nanostructures using spectroscopic ellipsometry

“…11 The additivity of bulk and NP response, as well as the relationship between Re[ ε j ] and ε L,j , can be explained under the hypothesis of a thin anisotropic NP layer, bulk isotropy, and alignment of the optical and crystallographic axes. Previous 085440-3 work defining a surface excess function [26][27][28] is adapted to make the anisotropic response explicit. The ASEF is given by…”

Reflectance Anisotropy of GaAs(100): Theory and Experiment

“…We calculate the optical properties by the sp 3 s ‫ء‬ tightbinding approach, which has proven successful for a number of homopolar surfaces [10][11][12]. To separate the contributions of the two opposite surfaces, which yield different optical properties, a linear cutoff function was used in calculating the optical matrix elements.…”

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Interaction between As and InP(110) studied by photoemission

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