Structure of the sulfur-passivated GaAs(001) surface

A soft x-ray standing wave measurement system for analyzing compound semiconductor surfaces prepared by molecular beam epitaxy

“…S atoms are at bridge site on the Ga-terminated GaAs͑001͒ surface forming Ga-S-Ga bridge bondings. The observed XSW profiles were slightly different from an (NH 4 ͒ 2 S x solution treated GaAs͑001͒ surface 16 which is rougher than the S-adsorbed GaAs͑001͒ surface. The ͑111͒ results yielded a P 111 of 0.826 Ϯ0.001 and an F 111 of 0.851Ϯ0.006, whereas the ͑111͒ results yielded a P 1 11 of 0.089Ϯ0.002 and an F 1 11 of 0.90 Ϯ0.01.…”

“…Furthermore the goniometer system was also improved for the soft-XSW triangulation studies. [15][16][17][18] Figure 1 schematically shows a top view of the developed apparatus, which consists of the fast entry chamber ͑load-lock chamber͒, the transfer chamber, the MBE growth chamber, and the analysis chamber which is connected to NTT's synchrotron radiation beam line. Samples can be prepared in the MBE chamber, and transferred through the transfer chamber to the analysis chamber without being exposed to the air.…”

“…16 In the ͑111͒ and ͑111͒ reflection experiments, the ͑001͒ direction should be inclined about 54°f rom the symmetric setup by rotating the axis. This value is larger than the ͑111͒ Bragg angle of 49.4°when we use photons of 2.5 keV.…”

“…XSW using synchrotron radiation soft x rays has recently been carried out at various facilities. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] When we use soft x rays as an incident beam, the larger cross sections of softer x rays for light-element atoms, such as Si and S, ensure higher emission intensity from monolayer-order quantities of these atoms, and photoelectrons and Auger electrons can be collected with sufficient statistics and energy resolution. Furthermore backreflection XSW, in which the incident photon energy of soft x rays is scanned instead of the incident angle, can be used for nonperfect substrate systems.…”

Density dependence of zinc-blende MnAs dots studied by X-ray absorption spectroscopy and X-ray magnetic circular dichroism

“…It is well known that the GaAs substrates terminated by group VI-element atoms such as sulfur or selenium have low surface energy, and thus enable a self-assembled growth of metallic clusters on the semiconductor [5]. To terminate the surface of GaAs substrates by sulfur, the substrate was first dipped into an (NH 4 ) 2 S x solution for 1 h, then rinsed with pure water.…”