Structural and electrical properties of Ge(111) films grown on Si(111) substrates and application to Ge(111)-on-Insulator

Sawano, Kentarou; Hoshi, Yusuke; Kubo, Shoichi; Arimoto, Keisuke; Yamanaka, Junji; Nakagawa, Kiyokazu; Hamaya, Kohei; Miyao, Masanobu; Shiraki, Y.

doi:10.1016/j.tsf.2015.11.020

Cited by 40 publications

(27 citation statements)

References 25 publications

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“…Using molecular beam epitaxy (MBE), we firstly formed an undoped Ge(111) layer (∼30 nm) grown at 350 • C (LT-Ge) on the undoped Si(111) substrate (ρ ∼ 1000 Ωcm), followed by an undoped Ge(111) layer (∼70 nm) grown at 700 • C (HT-Ge). [36,37] Next, we grew a 70-nm-thick phosphorous (P)-doped n-Si 0.1 Ge 0.9 (111) layer by MBE at 350 • C on top of the HT-Ge layer. The Ge content x in the SiGe layer was adjusted by controlling the deposition rates of Si and Ge, determined by x-ray diffraction (XRD) measurements of the SiGe layer grown on Ge(111) substrate.…”

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confidence: 99%

Pure spin current transport in a SiGe alloy

Naitô

Yamada

Tsukahara

et al. 2018

Appl. Phys. Express

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Using four-terminal nonlocal magnetoresistance measurements in lateral spin-valve devices with Si0.1Ge0.9, we study pure spin current transport in a degenerate SiGe alloy (n ∼ 5.0 × 10 18 cm −3 ). Clear nonlocal spin-valve signals and Hanle-effect curves, indicating generation, transport, and detection of pure spin currents, are observed. The spin diffusion length and spin lifetime of the Si0.1Ge0.9 layer at low temperatures are reliably estimated to be ∼0.5 µm and ∼0.2 ns, respectively. This study demonstrates the possibility of exploring physics and developing spintronic applications using SiGe alloys.

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confidence: 99%

Pure spin current transport in a SiGe alloy

Naitô

Yamada

Tsukahara

et al. 2018

Appl. Phys. Express

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“…We formed an undoped Ge(111) layer (∼28 nm) grown at 350 ○ C (LT-Ge) on a commercial undoped Si(111) substrate (ρ ∼ 1000 Ωcm), followed by an undoped Ge(111) layer (∼70 nm) grown at 700 ○ C (HT-Ge). [26] As the spin transport layer, we grew a 140-nm-thick phosphorous (P)-doped n-Ge(111) layer (doping concentration ∼ 10 19 cm −3 ) by molecular beam epitaxy (MBE) at 350 ○ C on top of the HT-Ge layer. The carrier concentration (n) in the n-Ge(111) layer was estimated to be n ∼ 1 × 10 19 cm −3 .…”

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confidence: 99%

Room-temperature spin transport in n-Ge probed by four-terminal nonlocal measurements

Yamada

Tsukahara

Fujita

et al. 2017

Appl. Phys. Express

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We demonsrtate electrical spin injection and detection in n-type Ge (n-Ge) at room temperature using four-terminal nonlocal spin-valve and Hanle-effect measurements in lateral spin-valve (LSV) devices with Heusler-alloy Schottky tunnel contacts. The spin diffusion length (λ Ge ) of the Ge layer used (n ∼ 1 × 10 19 cm −3 ) at 296 K is estimated to be ∼ 0.44 ± 0.02 µm. Room-temperature spin signals can be observed reproducibly at the low bias voltage range (≤ 0.7 V) for LSVs with relatively low resistance-area product (RA) values (≤ 1 kΩµm 2 ). This means that the Schottky tunnel contacts used here are more suitable than ferromagnet/MgO tunnel contacts (RA ≥ 100 kΩµm 2 ) for developing Ge spintronic applications.

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“…1(a). First, an undoped Ge(111) layer (∼28 nm) (LT-Ge) was grown at 350 • C on a commercial undoped Si(111) substrate (ρ ∼ 1000 Ωcm), followed by an undoped Ge(111) layer (∼70 nm) grown at 700 • C (HT-Ge), where we utilized the two-step growth technique by molecular beam epitaxy (MBE) [46]. Next, a 70nm-or 140-nm-thick phosphorus (P)-doped n + -Ge(111) layer (doping concentration ∼ 10 19 cm −3 ) was grown on top by MBE at 350 • C, as the spin transport layer.…”

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confidence: 99%

Nonmonotonic bias dependence of local spin accumulation signals in ferromagnet/semiconductor lateral spin-valve devices

et al. 2019

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We find extraordinary behavior of the local two-terminal spin accumulation signals in ferromagnet (FM)/semiconductor (SC) lateral spin-valve devices. With respect to the bias voltage applied between two FM/SC Schottky tunnel contacts, the local spin-accumulation signal can show nonmonotonic variations, including a sign inversion. A part of the nonmonotonic features can be understood qualitatively by considering the rapid reduction in the spin polarization of the FM/SC interfaces with increasing bias voltage. In addition to the sign inversion of the FM/SC interface spin polarization, the influence of the spin-drift effect in the SC layer and the nonlinear electrical spin conversion at a biased FM/SC contact are discussed.

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Structural and electrical properties of Ge(111) films grown on Si(111) substrates and application to Ge(111)-on-Insulator

Cited by 40 publications

References 25 publications

Pure spin current transport in a SiGe alloy

Pure spin current transport in a SiGe alloy

Room-temperature spin transport in n-Ge probed by four-terminal nonlocal measurements

Nonmonotonic bias dependence of local spin accumulation signals in ferromagnet/semiconductor lateral spin-valve devices

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