Room-temperature electroluminescence from germanium in an Al_03Ga_07As/Ge heterojunction light-emitting diode by Γ-valley transport

Cho, Seongjae; Park, Byung‐Gook; Yang, Changjae; Cheung, Samson; Yoon, Euijoon; Kamins, Theodore I.; Yoo, Sung Jin; Harris, James S.

doi:10.1364/oe.20.014921

Cited by 13 publications

(9 citation statements)

References 28 publications

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“…Figure 1 shows the band structures for unstrained and strainengineered Ge, illustrating the possibility of enhanced light emission through strain engineering [31]. Besides, Ge-based light sources on Si are important for the realization of future, nanoscale optical on-chip communication [32][33][34]. Light sources with directly-grown active materials are needed for the large-scale integration of highly-integrated photonic devices for optical interconnects in future high-capacity datacenters and high-performance computing applications.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneously grown tunable group-IV laser on silicon

et al. 2016

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Tunable tensile-strained germanium (epsilon-Ge) thin films on GaAs and heterogeneously integrated on silicon (Si) have been demonstrated using graded III-V buffer architectures grown by molecular beam epitaxy (MBE). epsilon-Ge epilayers with tunable strain from 0% to 1.95% on GaAs and 0% to 1.11% on Si were realized utilizing MBE. The detailed structural, morphological, band alignment and optical properties of these highly tensile-strained Ge materials were characterized to establish a pathway for wavelength-tunable laser emission from 1.55 μm to 2.1 μm. High-resolution X-ray analysis confirmed pseudomorphic epsilon-Ge epitaxy in which the amount of strain varied linearly as a function of indium alloy composition in the InxGa1-xAs buffer. Cross-sectional transmission electron microscopic analysis demonstrated a sharp heterointerface between the epsilon-Ge and the InxGa1-xAs layer and confirmed the strain state of the epsilon-Ge epilayer. Lowtemperature micro-photoluminescence measurements confirmed both direct and indirect bandgap radiative recombination between the Γ and L valleys of Ge to the light-hole valence band, with L-lh bandgaps of 0.68 eV and 0.65 eV demonstrated for the 0.82% and 1.11% epsilon-Ge on Si, respectively. The highly epsilon-Ge exhibited a direct bandgap, and wavelength-tunable emission was observed for all samples on both GaAs and Si. Successful heterogeneous integration of tunable epsilon-Ge quantum wells on Si paves the way for the implementation of monolithic heterogeneous devices on Si

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Section: Introductionmentioning

confidence: 99%

Heterogeneously grown tunable group-IV laser on silicon

et al. 2016

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“…Thus, the hybrid integration of germanium (Ge) and III–V materials-based optoelectronic devices with traditional Si CMOS technology would revolutionize technology needs in the near future. The superior transport properties and large modulation bandwidth of Ge and III–V compound semiconductor material systems make them ideal candidates for integration on Si. − Besides, Ge-based light sources on Si are important for the realization of future, nanoscale optical on-chip communication. − Furthermore, optical interconnects compatible with Si process technology are needed to provide for ever-increasing future bandwidth needs . Moreover, the electrical-to-optical interconnect transition for chip-to-chip communication is expected to be a gradual process depending upon specific application requirements and cost-performance trade-offs with current copper-based interconnect technologies …”

Section: Introductionmentioning

confidence: 99%

Heterogeneously-Grown Tunable Tensile Strained Germanium on Silicon for Photonic Devices

Clavel

Saladukha

Goley

et al. 2015

ACS Appl. Mater. Interfaces

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The growth, structural and optical properties, and energy band alignments of tensile-strained germanium (ε-Ge) epilayers heterogeneously integrated on silicon (Si) were demonstrated for the first time. The tunable ε-Ge thin films were achieved using a composite linearly graded InxGa1-xAs/GaAs buffer architecture grown via solid source molecular beam epitaxy. High-resolution X-ray diffraction and micro-Raman spectroscopic analysis confirmed a pseudomorphic ε-Ge epitaxy whereby the degree of strain varied as a function of the In(x)Ga(1-x)As buffer indium alloy composition. Sharp heterointerfaces between each ε-Ge epilayer and the respective In(x)Ga(1-x)As strain template were confirmed by detailed strain analysis using cross-sectional transmission electron microscopy. Low-temperature microphotoluminescence measurements confirmed both direct and indirect bandgap radiative recombination between the Γ and L valleys of Ge to the light-hole valence band, with L-lh bandgaps of 0.68 and 0.65 eV demonstrated for the 0.82 ± 0.06% and 1.11 ± 0.03% strained Ge on Si, respectively. Type-I band alignments and valence band offsets of 0.27 and 0.29 eV for the ε-Ge/In(0.11)Ga(0.89)As (0.82%) and ε-Ge/In(0.17)Ga(0.83)As (1.11%) heterointerfaces, respectively, show promise for ε-Ge carrier confinement in future nanoscale optoelectronic devices. Therefore, the successful heterogeneous integration of tunable tensile-strained Ge on Si paves the way for the design and implementation of novel Ge-based photonic devices on the Si technology platform.

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“…On the other hand, owing to its pseudo-direct bandgap with a magnitude of 0.8 eV (energy bandgap at k = 0), Ge is capable of realizing light emission at 1550-nm as a single-atom material without necessitating complicated epitaxy processing to adjust the atomic fractions accurately either in quaternary or quinary compound semiconductors. Therefore, Ge is considered as an optical material for active devices, such as laser and light-emitting diodes (LEDs) [11,12]. Ge can also be adopted to other active and passive devices including modulators, optical waveguides and photodetectors owing to its higher refractive index (n Ge = 4.0) than Si (n Si = 3.47), optical confinement stronger than Si and higher electron and hole mobilities, 3,900 cm 2 /V·s and 1,900 cm 2 /V·s, respectively [6,[13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Surface Treatment of Ge Grown Epitaxially on Si by Ex-Situ Annealing for Optical Computing by Ge Technology

Chen¹,

Huo²,

Cho³

et al. 2014

IEIE Transactions on Smart Processing and Computing

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Abstract:Ge is becoming an increasingly popular semiconductor material with high Si compatibility for on-chip optical interconnect technology. For a better manifestation of the meritorious material properties of Ge, its surface treatment should be performed satisfactorily before the electronic and photonic components are fabricated. Ex-situ rapid thermal annealing (RTA) processes with different gases were carried out to examine the effects of the annealing gases on the thin-film quality of Ge grown epitaxially on Si substrates. The Ge-on-Si samples were prepared in different structures using the same equipment, reduced-pressure chemical vapor deposition (RPCVD), and the samples annealed in N 2 , forming gas (FG), and O 2 were compared with the unannealed (deposited and only cleaned) samples to confirm the improvements in Ge quality. To evaluate the thin-film quality, room-temperature photoluminescence (PL) measurements were performed. Among the compared samples, the O 2 -annealed samples showed the strongest PL signals, regardless of the sample structures, which shows that ex-situ RTA in the O 2 environment would be an effective technique for the surface treatment of Ge in fabricating Ge devices for optical computing systems.

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Room-temperature electroluminescence from germanium in an Al_03Ga_07As/Ge heterojunction light-emitting diode by Γ-valley transport

Cited by 13 publications

References 28 publications

Heterogeneously grown tunable group-IV laser on silicon

Heterogeneously grown tunable group-IV laser on silicon

Heterogeneously-Grown Tunable Tensile Strained Germanium on Silicon for Photonic Devices

Surface Treatment of Ge Grown Epitaxially on Si by Ex-Situ Annealing for Optical Computing by Ge Technology

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