In 4d and As 3d core-levels for InAs(111)A-(2x2)S studied by synchrotron photoemission spectroscopy

Abstract

Recent studies carried out on the surface structures of the sulfur-adsorbed III-V compound semiconductor are reviewed. It was pointed out that for sulfur treated GaAs, (1 x 1) reconstructions were found for (111) surfaces, and that the (1 x 1) reconstruction was also observed for the InAs(111)B surface. However, recently the (2 x 2) reconstruction has been found for the sulfur-adsorbed (111)A surface. In this papers, the (2 x 2)S surface has been studied in details by Synchrotron Radiation Photoemission Spectroscopy (SRPES), and a probable model for the InAs(111)A-(2 x 2)S surface was discussed. As a sample, n-type InAs(111) with carrier density of 3 x 10(exp 17)/cu cm was used. Photons of 80 and 100 eV as well as detection angles 80 and zero degree were used for the measurements of In 4d and As 3d spectra, respectively. And, In 4d spectra and As 3d spectra measured for the InAs(111)-(2 x 2)S surface were shown in figures. As to the In 4d spectra, the binding energy positions of three doublet components of S1, S2 and S3 for that of bulk component were discussed. As to the As 3d spectra, only one doublet component was found to be fitted for both of the spectra measured at the detection angle of 80 and zero degrees. A structure model for the InAs(111)A-(2 x 2)S surface was proposed and shown in a figure.

硫黄吸着III?V族化合物半導体表面構造に関する最近の研究を概観した。硫黄処理したGaAsについて、(111)表面に代わって(1×1)再構成が発見されたこと、また、(1×1)再構成がInAs(111)B表面に対しても観測されたことを指摘した。しかし、最近、硫黄吸着(111)A表面に対して(2×2)再構成が行われることが分かった。本論文では、(2×2)S表面をシンクロトロン放射光電子分光法(SRPES)を使って詳細に研究し、InAs(111)A-(2×2)S表面に適した推定モデルを論じた。試料として、キャリア密度が3×10(exp 17)/立方センチメートルのn-型InAs(111)を使用した。Inの4dとAsの3dスペクトル測定には、それぞれ80eVおよび100eVのフォトン、ならびに80度と0度の検出角度を用いた。InAs(111)-(2×2)S表面に対して測定したInの4dスペクトルとAsの3dスペクトルを図に示した。Inの4dスペクトルについては、バルク成分のエネルギー位置に対するS1、S2およびS3の3本の2重項成分の結合エネルギー位置を論じた。Asの3dスペクトルについては、1本の2重項成分だけが、80度と0度の検出角度で測定したスペクトルの両方に適合することが分かった。InAs(111)A-(2×2)S表面に対する構造モデルを提案し、図を示した。