Effect of Annealing on the Density of Defects in Epitaxial CdTe (211)/GaAs
| Autor: | Yusuf Selamet, Emine Bakali, Enver Tarhan |
|---|---|
| Přispěvatelé: | Izmir Institute of Technology, Bakali, Emine, Selamet, Yusuf, Tarhan, Enver, Izmir Institute of Technology. Physics |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
MBE Annealing (metallurgy) Thin films Dislocations 02 engineering and technology 01 natural sciences symbols.namesake Etch pit density 0103 physical sciences Materials Chemistry Cadmium telluride Wafer Electrical and Electronic Engineering Thin film 010302 applied physics business.industry 021001 nanoscience & nanotechnology Condensed Matter Physics Electronic Optical and Magnetic Materials Thermal cycle annealing EPD Raman spectroscopy symbols Optoelectronics Dislocation 0210 nano-technology business Molecular beam epitaxy Raman scattering Annealing parameters |
| Popis: | Bakali, Emine/0000-0002-5486-5769 WOS: 000437146400080 CdTe thin films were grown on GaAs (211) wafers by molecular beam epitaxy as the buffer layer for HgCdTe infrared detector applications. We studied the effect of annealing on the density of dislocation of these CdTe thin films under varying annealing parameters such as annealing temperature, annealing duration, and number of cycles. Annealings were carried out using a homemade annealing reactor possessing a special heater element made of a Si wafer for rapid heating. The density of dislocations, which were made observable with a scanning electron microscope after etching with an Everson solution, were calculated by counting the number of dislocations per unit surface area, hence the term etch pit density (EPD). We were able to decrease EPD values by one order of magnitude after annealing. For example, the best EPD value after a 20-min annealing at 400A degrees C was similar to 2 x 10(7) cm(-2) for a 1.63-mu m CdTe thin film which was about 9.5 x 10(7) cm(-2) before annealing. We also employed Raman scattering measurements to see the changes in the structural quality of the samples. From the Raman measurements, we were able to see improvements in the quality of our samples from the annealing by studying the ratio of 2LO/LO phonon mode Raman intensities. We also observed a clear decrease in the intensity of Te precipitations-related modes, indicating a decrease in the size and number of these precipitations. |
| Databáze: | OpenAIRE |
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