摘要:

The effects of hydrogen plasma exposure on the concentration of donors in high‐purity lightly Si‐doped molecular beam epitaxial GaAs have been investigated by photothermal ionization spectroscopy, low‐temperature photoluminescence, capacitance‐voltage, and Hall‐effect measurements. Photothermal ionization measurements show that in addition to Si donors S and Ge donors are present in the original high‐purity samples. After hydrogenation, the Si donor concentration is significantly reduced with a corresponding increase in mobility. Low‐temperature photoluminescence also showed a decrease in the full width at half‐maximum of the neutral donor bound exciton line indicating that the total impurity concentration is reduced. These results provide spectroscopic evidence to support the neutralization of Si donors confirming earlier results of the effects of hydrogen plasma exposure in GaAs.

ISSN:0003-6951    

DOI:10.1063/1.97712

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Indium alloyed TbFe amorphous films for use as a magneto‐optic memory are proposed and studied. These TbFeIn films show strong resistance to corrosion and oxidation. Indium is effective in suppressing oxygen diffusion into the films. An oxygen diffusion coefficient of 5×10−25m2/s is calculated for TbFeIn films incubated at room temperature. Activation energy is 1.3 eV. This value is over 1.5 times larger than that of TbFe films, where the value is obtained with ellipsometry measurements by R. Allen and G. A. N. Connell [J. Appl. Phys.53, 2353 (1982)].

ISSN:0003-6951    

DOI:10.1063/1.98249

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Product translational energy distributions have been used in previous studies as a diagnostic of surface reaction enhancement mechanisms under ion bombardment. Haring and co‐workers [R. A. Haring, A. Haring, F. W. Saris, and A. E. de Vries, Appl. Phys. Lett.41, 174 (1982)] have taken anE−2dependence for SiFxspecies desorbing during ion‐enhanced etching of silicon as evidence for the importance of physical sputtering. In this work, the translational energy distribution of SiF4desorbing from the surface of silicon during spontaneous etching by XeF2has been obtained from modulated beam measurements. The distribution deviates markedly from a thermal distribution at the surface temperature and exhibits anE−2dependence at high energy. Observation of this energy dependence both with and without ions suggests that translational energy distributions may not provide a unique signature for chemical and physical sputtering.

ISSN:0003-6951    

DOI:10.1063/1.97713

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A two‐element molybdenum‐silicon multilayer monochromator has been tested in the energy range 60–110 eV on a differentially pumped bending magnet beamline having a high‐energy cutoff of 3.5 keV at the Stanford Synchrotron Radiation Laboratory. The multilayer structures were sputter deposited onto 5‐cm‐diam (111) single‐crystal silicon and contained 20 molybdenum layers (4.93 nm thick) separated by amorphous silicon layers (7.8 nm thick). A 1200 l/mm gold transmission grating was used to independently measure the wavelength passed by the monochromator. The AlL2,3absorption edge jump was also measured using the monochromator. These experimental results are compared to model calculations for both the synchrotron source‐monochromator and the synchrotron source‐monochromator‐Al filter configurations and excellent agreement is shown.

ISSN:0003-6951    

DOI:10.1063/1.97714

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

In the development of high‐power free‐electron lasers, intense electron beams are required. Large area, directly heated lanthanum hexaboride cathodes have been proposed as the electron emitter. To aid in the design of the cathode, the resistivity of lanthanum hexaboride as a function of material density and temperature has been measured.

ISSN:0003-6951    

DOI:10.1063/1.97715

出版商:AIP    

年代:1987

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.98271

出版商:AIP    

年代:1987

数据来源: AIP