Crystalline and Electrical Properties of $mathrm{Ge}_{1-mathrm{x}}mathrm{Sn}_{mathrm{x}}/mathrm{Ge}_{1-mathrm{x}-mathrm{y}}mathrm{Si}_{mathrm{x}}mathrm{Sn}_{mathrm{y}}$ Quantum Well Structures

The crystalline and electrical properties of $\mathrm{Ge}_{1-\mathrm{x}}\mathrm{Sn}_{\mathrm{x}}/\mathrm{Ge}_{1-\mathrm{x}-\mathrm{y}}\mathrm{Si}_{\mathrm{x}}\mathrm{Sn}_{\mathrm{y}}$ quantum well (QW) structures have been investigated. We fabricated QW samples with QW structure of 15-nm-thick Ge 0.91 Sn 0.09 well without any spacer layers (sample A) and 2-nm-thick Ge 0 . 91 Sn 0 . 09 well with GeSn (Sn: 1-2%) spacer layers (sample B). From current density-voltage (J-V) characterizations at 10 K, both QW diode samples exhibited non-Ohmic characteristics. Moreover, a peak obviously exists at ~0.5 V in the forward bias region for sample B. This result infers the potential to further develop $\mathrm{Ge}_{1-\mathrm{x}}\mathrm{Sn}_{\mathrm{x}}$ -based resonant tunneling diodes by using the $\mathrm{Ge}_{1-\mathrm{x}}\mathrm{Sn}_{\mathrm{x}}/\mathrm{Ge}_{1-\mathrm{x}-\mathrm{y}}\mathrm{Si}_{\mathrm{x}}\mathrm{Sn}_{\mathrm{y}}$ QW structure.