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We report high quality GeSn/GaAs heterostructure photodetectors grown by a modified magnetron sputtering system. A metal-semiconductor-metal photoconductor is fabricated to examine the ability of photodetection for GeSn alloy. Then the GeSn/GaAs heterostructure photodetector is first demonstrated with a detectivity of $1.8\times 10^{9}$ Jones achieved at 1450 nm under an applied reverse voltage bias of −0.1 V, which is comparable to or even better than the GeSn-based photodetectors grown by chemical vapor deposition. The work provides an alternative technique for low cost and large-area fabrication of GeSn based devices. [ABSTRACT FROM AUTHOR]

We report the growth of direct bandgap single-crystalline Ge1−xSnx thin films on unheated substrates by a modified magnetron sputtering system. The Ge1−xSnx thin films were deposited on Si, Ge, and GaAs substrates at room temperature. They were characterized by X-ray diffraction and X-ray photoelectron spectroscopy that revealed the existence of Ge1−xSnx (004) peak and Ge-Sn bonds. Transmission and photoluminescence (PL) measurements confirm the direct bandgap dominated transition, and the bandgap values obtained are in agreement with the results calculated by 8-band k.p method. This article provides a simple and cost-effect way for fabrication direct bandgap GeSn films. [ABSTRACT FROM AUTHOR]

Ge x Sn 1-x is one of the most promising materials in optoelectronics for its direct band-gap nature. In this paper, we report high-quality Ge and Sn thin films deposited on Si (001) substrates by magnetron sputtering. We found that the growth power and chamber pressure affect the quality of the Ge and Sn thin films significantly but in different ways. By optimizing the deposition conditions, high quality Ge and Sn films are achieved. A clear peak of Ge (004) phase in the x-ray diffraction (XRD) pattern which indicates a high-quality Ge lattice formed is observed, and post-treatment like rapid thermal annealing does not significantly affect the quality of the thin films. [ABSTRACT FROM AUTHOR]