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.