Total electron yield XAFS investigations of ZnTe/CdSe superlattice interfaces. [XAFS (x-ray absorption fine structure)]

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7112315

Kemner, K M

This work has primarily dealt with two topics: (1) The development of a total electron yield detector that operates near the boiling point of liquid nitrogen and (2) the use of the detector to investigate the interfaces of ZnTe/CdSe superlattices. The detector has been used to perform XAFS measurements at 80K in the total electron yield mode on Au and GaAs. Transmission measurements have also been performed on Au and GaAs at liquid nitrogen temperatures. Excellent agreement is found between the data obtained using these two techniques. This answers the very important question of amplitude transferability between the total electron yield and transmission techniques. XAFS, employing the total electron yield technique, as well as x-ray diffraction, has been used to study the local atomic structure of four different short period ZnTe/CdSe(001) superlattices grown by molecular-beam epitaxy. The data indicate Zn-Se and Cd-Te coordination numbers greater than those expected for sharp interfaces in the superlattice. Although strain would appear to suppress interdiffusion, it has been shown that the results are consistent with an interchange of the Zn and Cd atomic plane across the Zn-Se interface and Se and Te atomic planes across the Cd-Te interface. Theoretically, this switch of atomic planes has been shown to be energetically favorable by comparing the changes in chemical bond formation energies and strain energies between a perfect superlattice and one with the above mentioned switching of atomic planes. Accommodation of this strain is shown through bond bending and bond stretching at the newly formed strain interfaces. Combining the x-ray diffraction and XAFS techniques seems to be very promising and could be used on many other short-period superlattice systems.

• Research Organization: Notre Dame Univ., IN (United States)
• OSTI ID: 7112315
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
CADMIUM COMPOUNDS
CADMIUM SELENIDES
CHALCOGENIDES
COHERENT SCATTERING
COORDINATION NUMBER
DIFFRACTION
EPITAXY
INTERFACES
MOLECULAR BEAM EPITAXY
SCATTERING
SELENIDES
SELENIUM COMPOUNDS
SPECTRA
SPECTROSCOPY
SUPERLATTICES
TELLURIDES
TELLURIUM COMPOUNDS
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
ZINC COMPOUNDS
ZINC TELLURIDES