Optoelectronic properties of high-Si-content-Ge_1−x–y Si _x Sn _y /Ge_1−x Sn _x /Ge_1−x–y Si _x Sn _y double heterostructure

Abstract

The optoelectronic properties of Ge 1−x−y Si x Sn y /Ge 1−x Sn x /Ge 1−x−y Si x Sn y double heterostructures pseudomorphically grown on a Ge substrate were investigated. The photoluminescence (PL) intensity of the sample with Ge 0.66 Si 0.23 Sn 0.11 cladding layers is three times larger compared to PL from structure with a Ge cladding layer, which can be attributed to higher energy band offsets at both conduction and valence band edges at the Ge 0.91 Sn 0.09 /Ge 0.66 Si 0.23 Sn 0.11 interface. The PL spectrum of the sample with the Ge 0.66 Si 0.23 Sn 0.11 cladding layer at room temperature can be deconvoluted into four components, and the origins of these components can be assigned to direct and indirect transitions by measuring the temperature dependence of each component's intensity. In addition, we examined the formation and characterization of strain-relaxed Ge 1−x−y Si x Sn y /Ge 1−x Sn x /Ge 1−x−y Si x Sn y double heterostructures to relieve the compressive strain in the Ge 1−x Sn x layer. Stacking faults were observed in the Ge 1−x Sn x and Ge 1−x−y Si x Sn y layers. The PL peak intensity of the strainrelaxed Ge 1−x Sn x layer decreases by a factor of 1/20 compared to the PL peak intensity of the double heterostructure pseudomorphically grown on a Ge(001) substrate. In addition, PL intensity can be increased by post-deposition annealing owing to decreasing defects.

Formation and optoelectronic property of strain-relaxed Ge1−x−y Si x Sn y /Ge1−x Sn x /Ge1−x−y Si x Sn y double heterostructures on a boron-ion-implanted Ge(001) substrate

“…Figure 4 shows the PL spectrum obtained at room temperature from the sample grown on ion-implanted Ge substrate with pre-annealing. Also, we show the PL spectrum obtained previously from the Ge 0.48 Si 0.33 Sn 0.19 (15 nm)/Ge 0.91 Sn 0.09 (15 nm)/Ge 0.48 Si 0.33 Sn 0.19 (50 nm) double heterostructure with a DSR value of 22% in all layers grown on virtual Ge (v-Ge) substrate for comparison 21) In addition, the PL spectrum obtained from a pseudomorphically grown Ge 1−x−y Si x Sn y (30 nm)/Ge 1−x Sn x (15 nm)/Ge 1−x−y Si x Sn y (30 nm) double heterostructure sample [as shown in Figs. 1(g)-1(h)] with a DSR value of 0% in all layers is also shown (dashed line).…”

“…We could practically confirm the improvement of the carrier confinement effect on the photoluminescence spectroscopy. 20,21) On the other hand, in our previous heterostructures, a serious problem remained toward lasing at room temperature, i.e. the indirect bandgap of the Ge 1−x Sn x layer pseudomorphically grown on a Ge substrate due to a large compressive strain.…”

Photoluminescence properties of heavily Sb doped Ge1−x Sn x and heterostructure design favorable for n+-Ge1−x Sn x active layer

“…In contrast, the PL peak position was approximately 0.64 eV. According to our previous report, 21) the positions of PL peaks related to L and Γ points for a pseudomorphic Ge 0.91 Sn 0.09 layer grown on Ge are approximately 0.60 and 0.70 eV, respectively. According to our bandgap calculation [see supplementary data SD2 (available online at stacks.iop.…”

“…In our previous study, we demonstrated the formation of Si x Ge 1−x−y Sn y /Ge 1−x Sn x /Si x Ge 1−x−y Sn y DHSs and high photoluminescence (PL) intensity of a 15 nm thick Ge 1−x Sn x active layer when carriers are sufficiently confined using the Si x Ge 1−x−y Sn y clad layer. 21) Although such results seem promising for the optoelectronic application of Ge 1−x Sn x , the issue of indirect bandgap nature of the Ge 1-x Sn x layer should be overcome. To this end, our group investigated a strain-relaxed direct-bandgap Ge 1−x Sn x on ionimplanted substrate.…”

Sn-incorporation effect on thermoelectric properties of Sb-doped Ge-rich Ge1−x−y Si x Sn y epitaxial layers grown on GaAs(001)

“…1,[3][4][5][6] This means that a quantum confinement structure suitable for device applications such as light-emitting diodes, semiconductor lasers, and high electron mobility transistors can be realized using only strain-free group-IV semiconductors. Several groups, including us, recently demonstrated the crystal growth of type-I band structures, specifically, Ge 1−x−y Si x Sn y /Ge junction, 7) Ge 1−x−y Si x Sn y /Ge 1−x Sn x / Ge 1−x−y Si x Sn y double heterojunctions, [8][9][10][11] and the multiquantum well. [12][13][14] They showed Ge 1−x−y Si x Sn y 's high potential for use in the cladding layers of lasers and resonant tunneling diodes.…”