Germanium based photonic components toward a full silicon/germanium photonic platform
01 Jun 2017-Progress in Crystal Growth and Characterization of Materials (Pergamon)-Vol. 63, Iss: 2, pp 1-24
TL;DR: In this paper, the authors show that optical germanium-on-insulator (GeOI) substrates fabricated by the Smart Cut™ technology is a key feature for future Si-complementary metal oxide Semiconductor (CMOS) compatible laser demonstration.
About: This article is published in Progress in Crystal Growth and Characterization of Materials.The article was published on 2017-06-01. It has received 60 citations till now. The article focuses on the topics: Germanium & Silicon photonics.
Citations
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TL;DR: In this article, the authors reported a longer emitted wavelength and a significant improvement in lasing temperature using higher Sn content GeSn layers of optimized crystalline quality, grown on graded Sn content buffers using Reduced Pressure CVD.
Abstract: Recent demonstrations of optically pumped lasers based on GeSn alloys put forward the prospect of efficient laser sources monolithically integrated on a Si photonic platform. For instance, GeSn layers with 12.5% of Sn were reported to lase at 2.5 um wavelength up to 130 K. In this work, we report a longer emitted wavelength and a significant improvement in lasing temperature. The improvements resulted from the use of higher Sn content GeSn layers of optimized crystalline quality, grown on graded Sn content buffers using Reduced Pressure CVD. The fabricated GeSn micro-disks with 13% and 16% of Sn showed lasing operation at 2.6 um and 3.1 um wavelengths, respectively. For the longest wavelength (i.e 3.1 um), lasing was demonstrated up to 180 K, with a threshold of 377 kW/cm2 at 25 K.
157 citations
TL;DR: In this article, a longer emitted wavelength and a significant improvement in lasing temperature were reported for GeSn micro-disks with higher Sn content GeSn layers of optimized crystalline quality.
Abstract: Recent demonstrations of optically pumped lasers based on GeSn alloys put forward the prospect of efficient laser sources monolithically integrated on a Si photonic platform. For instance, GeSn layers with 12.5% of Sn were reported to lase at 2.5 μm wavelength up to 130 K. In this work, we report a longer emitted wavelength and a significant improvement in lasing temperature. The improvements resulted from the use of higher Sn content GeSn layers of optimized crystalline quality, grown on graded Sn content buffers using reduced pressure CVD. The fabricated GeSn micro-disks with 13% and 16% of Sn showed lasing operation at 2.6 μm and 3.1 μm wavelengths, respectively. For the longest wavelength (i.e., 3.1 μm), lasing behavior was demonstrated up to 180 K, with a threshold of 377 kW/cm2 at 25 K.
137 citations
TL;DR: Germanium has played a key role in silicon photonics as an enabling material for datacom applications as discussed by the authors, and the unique properties of Ge have been leveraged to develop high performance integrated photodectors, which are now mature devices.
Abstract: Germanium (Ge) has played a key role in silicon photonics as an enabling material for datacom applications. Indeed, the unique properties of Ge have been leveraged to develop high performance integrated photodectors, which are now mature devices. Ge is also very useful for the achievement of compact modulators and monolithically integrated laser sources on silicon. Interestingly, research efforts in these domains also put forward the current revolution of mid-IR photonics. Ge and Ge-based alloys also present strong advantages for mid-infrared photonic platform such as the extension of the transparency window for these materials, which can operate at wavelengths beyond 8 μm. Different platforms have been proposed to take benefit from the broad transparency of Ge up to 15 μm, and the main passive building blocks are now being developed. In this review, we will present the most relevant Ge-based platforms reported so far that have led to the demonstration of several passive and active building blocks for mid-IR photonics. Seminal works on mid-IR optical sensing using integrated platforms will also be reviewed.
128 citations
TL;DR: In this paper, the authors present a fully integrated, reconfigurable and scalable platform operating in the near-field regime that performs controlled heat extraction and energy recycling, which enables precise positioning of a thermal emitter within nanometer distances from a room-temperature germanium photodetector to form a thermo-photovoltaic cell.
Abstract: Energy transferred via thermal radiation between two surfaces separated by nanometer distances can be much larger than the blackbody limit. However, realizing a scalable platform that utilizes this near-field energy exchange mechanism to generate electricity remains a challenge. Here, we present a fully integrated, reconfigurable and scalable platform operating in the near-field regime that performs controlled heat extraction and energy recycling. Our platform relies on an integrated nano-electromechanical system that enables precise positioning of a thermal emitter within nanometer distances from a room-temperature germanium photodetector to form a thermo-photovoltaic cell. We demonstrate over an order of magnitude enhancement of power generation (Pgen ~ 1.25 μWcm−2) in our thermo-photovoltaic cell by actively tuning the gap between a hot-emitter (TE ~ 880 K) and the cold photodetector (TD ~ 300 K) from ~ 500 nm down to ~ 100 nm. Our nano-electromechanical system consumes negligible tuning power (Pgen/PNEMS ~ 104) and relies on scalable silicon-based process technologies. Designing a scalable platform to generate electricity from the energy exchange mechanism between two surfaces separated by nanometer distances remains a challenge. Here, the authors demonstrate reconfigurable, scalable and fully integrated near-field thermo-photovoltaics for on-demand heat recycling.
81 citations
TL;DR: In this paper, a normal incidence vertical p-i-n photodetectors on a germanium-on-insulator (GOI) platform were demonstrated.
Abstract: In this paper, normal incidence vertical p-i-n photodetectors on a germanium-on-insulator (GOI) platform were demonstrated. The vertical p-i-n structure was realized by ion-implanting boron and arsenic at the bottom and top of the Ge layer, respectively, during the GOI fabrication. Abrupt doping profiles were verified in the transferred high-quality Ge layer. The photodetectors exhibit a dark current density of ∼47 mA/cm2 at −1 V and an optical responsivity of 0.39 A/W at 1550 nm, which are improved compared with state-of-the-art demonstrated GOI photodetectors. An internal quantum efficiency of ∼97% indicates excellent carrier collection efficiency of the device. The photodetectors with mesa diameter of 60 μm exhibit a 3 dB bandwidth of ∼1 GHz, which agrees well with theoretical calculations. The bandwidth is expected to improve to ∼32 GHz with mesa diameter of 10 μm. This work could be similarly extended to GOI platforms with other intermediate layers and potentially enrich the functional diversity of GOI for near-infrared sensing and communication integrated with Ge CMOS and mid-infrared photonics.
50 citations
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