In Situ Band-Edge Monitoring of Cd1−yZnyTe Substrates for Molecular Beam Epitaxy of HgCdTe
| Autor: | L. A. Almeida, B. Pinkie, B. Wissman, Alexander Brown, R. N. Jacobs, Andrew J. Stoltz, J. D. Benson, J. Arias |
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| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
In situ Materials science Oxide Nucleation Analytical chemistry 02 engineering and technology Substrate (electronics) 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Electronic Optical and Magnetic Materials chemistry.chemical_compound Wavelength chemistry Desorption 0103 physical sciences Materials Chemistry Electrical and Electronic Engineering Dislocation 0210 nano-technology Molecular beam epitaxy |
| Zdroj: | Journal of Electronic Materials. 48:6138-6144 |
| ISSN: | 1543-186X 0361-5235 |
| DOI: | 10.1007/s11664-019-07354-9 |
| Popis: | We demonstrate the benefits of in situ band-edge monitoring of CdZnTe substrates for molecular beam epitaxy (MBE). The production of large-area Cd1−yZnyTe(211)B substrates up to and exceeding 8 × 8 cm2 brings new challenges from the perspective of MBE growth of Hg1−xCdxTe. Localized variation of the Zn concentration, even less than y = 0.01, can potentially cause variation in lattice-misfit with the HgCdTe epi-layers potentially resulting in ∼ 10 × difference in etch-pit density. Variation in Zn concentration is expected to be greater over larger substrates, and thus local differences in dislocation density may also be expected. The substrate Zn concentration has been determined using in situ band-edge measurement prior to nucleation of HgCdTe. Ex situ infrared transmission spectra has been used to confirm the validity of in situ band-edge wavelength measurements. We also examine the usefulness of band-edge thermometry (BET), for monitoring substrate temperature during Te/oxide desorption and for nucleation of HgCdTe epi-layers. In principle, knowledge of the exact Zn content across the largest area of the substrate, allows for tuning growth parameters to maximize yield of perfectly lattice-matched material. |
| Databáze: | OpenAIRE |
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