Rodolfo Camacho-Aguilera | Massachusetts Institute of Technology (MIT) (original) (raw)
Papers by Rodolfo Camacho-Aguilera
Advanced Functional Materials, Mar 10, 2009
A series of push‐pull azo compounds containing bulky substituents are synthesized, yielding fully... more A series of push‐pull azo compounds containing bulky substituents are synthesized, yielding fully amorphous materials with glass‐transition temperatures above 200 °C. Thin films are subjected to holographic illumination and show superior bulk photomigration in terms of speed and efficiency compared to materials exhibiting similar electronic and photochromic properties in the solid state. The reported results give evidence that a microscopic consideration of the free volume rather than macroscopic parameters like the glass‐transition temperature should to be adopted to interpret the matrix stiffness and its deformation ability. Irradiation performed at higher laser intensity produces periodic superstructures whose height is five to six times as high as the initial film thickness. The surface tension and instability effects are put forward to interpret the growth of such superstructures.
ECS Meeting Abstracts, 2010
not Available.
Proceedings of SPIE, Feb 19, 2014
ABSTRACT Ge-on-Si devices are explored for photonic integration. Through the development of bette... more ABSTRACT Ge-on-Si devices are explored for photonic integration. Through the development of better growth techniques, monolithic integration, laser design and prototypes, it was possible to probe Ge light emitters with emphasis on lasers. Preliminary worked shows thermal photonic behavior capable of enhancing lamination at high temperatures. Increase luminescence is observed up to 120°C from L-band contribution. Higher temperatures show contribution from Δ -band. The increase carrier thermal contribution suggests high temperature applications for Ge light emitters. A Ge electrically pumped laser was probed under 0.2% biaxial strain and doping concentration ~4.5×1019cm-3 n-type. Ge pnn lasers exhibit a gain >1000cm-1 with 8mW power output, presenting a spectrum range of over 200nm, making Ge the ideal candidate for Si photonics. Large temperatures fluctuations and process limit the present device. Theoretically a gain of >4000cm- gain is possible with a threshold of as low as 1kA/cm2. Improvements in Ge work
Frontiers in Optics 2010/Laser Science XXVI, 2010
Monolithic lasers on silicon are ideal for large-scale, high volume electronic-photonic integrati... more Monolithic lasers on silicon are ideal for large-scale, high volume electronic-photonic integration for high performance and high-energy efficiency information technologies [1]. Germanium is a particularly interesting candidate due to its compatibility with Si-based complementary ...
Advanced Photonics, 2011
... Rodolfo Camacho-Aguilera1, Jonathan Bessette1, Yan Cai1, Xiaoman Duan1, Jifeng Liu2, Lionel K... more ... Rodolfo Camacho-Aguilera1, Jonathan Bessette1, Yan Cai1, Xiaoman Duan1, Jifeng Liu2, Lionel Kimerling1, Jurgen Michel1 1Massachusetts Institute of Technology, 77 Massachusetts Ave Cambridge, MA, 02139 2Thayer School of Engineering at Dartmouth College, 8000 ...
IEEE Journal of Selected Topics in Quantum Electronics, 2013
We analyze the optical gain of tensile-strained, n-germanium (n-Ge) material taking bandgap narro... more We analyze the optical gain of tensile-strained, n-germanium (n-Ge) material taking bandgap narrowing (BGN) for heavily doped Ge into account. Both the direct bandgap and indirect bandgap are narrowed by 60 meV. Our new modeling explains the wide lasing spectrum of 1520-1700 nm in electrically pumped Ge lasers. The calculated materials gain can reach 1000 cm-1 when the injected carrier density is ~mid-1019 cm-3 with a combination of 0.25% tensile strain and 4.5×1019 cm-3 n-type doping. The threshold current density is estimated to be 0.53 kA/cm2 for an optimized edge-emitting double-heterojunction Ge device, comparable to bulk III-V lasers. We also review current progress on Ge quantum-well (QW) structures. The threshold current density of most Ge QW structures is similar to bulk Ge. Only tensile-strained QWs show reduced threshold currents.
ECS Transactions, 2013
We study the phosphorous (P) diffusion in Ge grown on Si substrate with different background dopi... more We study the phosphorous (P) diffusion in Ge grown on Si substrate with different background doping and we find that the diffusion coefficient is extrinsic and is enhanced by over 500 times in Ge doped at 1x1019 cm-3 compared to diffusivity in intrinsic Ge. We study the loss mechanisms in Ge-on-Si. We show that the doping level is a result of the balance between in-diffusion and dopant loss. The high diffusivity in doped Ge leads to a uniform distribution of P in Ge with the concentration above 4.5x1019 cm-3.
Optics Express, 2012
Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demon... more Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demonstrated. Room temperature multimode laser with 1mW output power is measured. Phosphorous doping in Germanium at a concentration over 4x10 19 cm −3 is achieved. A Germanium gain spectrum of nearly 200nm is observed. integration of room-temperature cw GaAs/AlGaAs lasers on Si substrates via relaxed graded GeSi buffer layers," J. Appl. Phys. 93(1), 362-367 (2003). 3. H. Park, A. Fang, S. Kodama, and J. Bowers, "Hybrid silicon evanescent laser fabricated with a silicon waveguide and III-V offset quantum wells," Opt. Express 13(23), 9460-9464 (2005).
National Fiber Optic Engineers Conference, 2012
... Jurgen Michel1, Rodolfo E. Camacho-Aguilera1, Yan Cai1, Neil Patel1, Jonathan T. Bessette1, M... more ... Jurgen Michel1, Rodolfo E. Camacho-Aguilera1, Yan Cai1, Neil Patel1, Jonathan T. Bessette1, Marco Romagnoli1,2, Birendra (Raj) Dutt2,3, Lionel C. Kimerling1 1Massachusetts Institute of Technology, 77 Massachusetts Ave ... Page 2. secondary ion mass spectrometry (SIMS). ...
The 9th International Conference on Group IV Photonics (GFP), 2012
ABSTRACT CMOS Ge-on-Si pnn multimode laser diode is demonstrated. Calculated losses suggest a gai... more ABSTRACT CMOS Ge-on-Si pnn multimode laser diode is demonstrated. Calculated losses suggest a gain above 100cm-1. Observed power of above 1mW is reported.
Advanced Photonics Congress, 2012
ABSTRACT Germanium lasing from Ge-on-Si pnn heterojunction diode structures is demonstrated. Sele... more ABSTRACT Germanium lasing from Ge-on-Si pnn heterojunction diode structures is demonstrated. Selective growth of highly phosphorus doped Ge in oxide trenches shows a design for CMOS compatible laser integration.
Optics Express, 2012
Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demon... more Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demonstrated. Room temperature multimode laser with 1mW output power is measured. Phosphorous doping in Germanium at a concentration over 4x10 19 cm −3 is achieved. A Germanium gain spectrum of nearly 200nm is observed. integration of room-temperature cw GaAs/AlGaAs lasers on Si substrates via relaxed graded GeSi buffer layers," J. Appl. Phys. 93(1), 362-367 (2003). 3. H. Park, A. Fang, S. Kodama, and J. Bowers, "Hybrid silicon evanescent laser fabricated with a silicon waveguide and III-V offset quantum wells," Opt. Express 13(23), 9460-9464 (2005).
Optics Letters, 2010
Monolithic lasers on Si are ideal for high volume and large-scale electronic-photonic integration... more Monolithic lasers on Si are ideal for high volume and large-scale electronic-photonic integration. Ge is an interesting candidate due to its pseudo-direct gap properties and compatibility with Si complementary metal oxide semiconductor (CMOS) technology. Recently we have demonstrated room temperature photoluminescence, electroluminescence and optical gain from the direct gap transition of band-engineered Ge-on-Si using tensile strain and n-type doping. Here we report the first experimental observation of lasing from the direct gap transition of Ge-on-Si at room temperature using an edge emitting waveguide device. The emission exhibited a gain spectrum of 1590-1610 nm, line narrowing and polarization evolution from a mixed TE/TM to predominantly TE with increasing gain, and a clear threshold behavior.
Thin Solid Films, 2012
Electronic-photonic synergy has become an increasingly clear solution to enhance the bandwidth an... more Electronic-photonic synergy has become an increasingly clear solution to enhance the bandwidth and improve the energy efficiency of information systems. Monolithic integration of optoelectronic devices is the ideal solution for large-scale electronic-photonic synergy. Due to its pseudo-direct gap behavior in optoelectronic properties and compatibility with Si electronics, epitaxial Ge-on-Si has become an attractive solution for monolithic optoelectronics. In this paper we will review recent progress in Ge-on-Si optoelectronics, including photodetectors, electroabsorption modulators, and lasers. The performance of these devices has been enhanced by band-engineering such as tensile strain and n-type doping, which transforms Ge towards a direct gap material. Selective growth reduces defect density and facilitates monolithic integration at the same time. Ge-on-Si photodetectors have approached or exceeded the performance of their III-V counterparts, with bandwidth-efficiency product > 30 GHz for p-i-n photodiodes and bandwidth-gain product > 340 GHz for avalanche photodiodes. Enhanced Franz-Keldysh effect in tensile-strained Ge offers ultralow energy photonic modulation with b 30 fJ/bit energy consumption and > 100 GHz intrinsic bandwidth. Room temperature optically-pumped lasing as well as electroluminescence has also been achieved from the direct gap transition of band-engineered Ge-on-Si waveguides. These results indicate that band-engineered Ge-on-Si is promising to achieve monolithic active optoelectronic devices on a Si platform.
Ge-on-Si devices are explored for photonic integration. Importance of Ge in photonics has grown a... more Ge-on-Si devices are explored for photonic integration. Importance of Ge in photonics has grown and through techniques developed in our group we demonstrated low density of dislocations (<1x109cm-2) and point defects Ge growth for photonic devices. The focus of this document will be exclusively on Ge light emitters. Ge is an indirect band gap material that has shown the ability to act like a pseudo direct band gap material. Through the use of tensile strain and heavy doping, Ge exhibits properties thought exclusive of direct band gap materials. Dependence on temperature suggests strong interaction between indirect bands, [Delta] and L, and the direct band gap at [Gamma]. The behavior is justified through increase in photoluminescence on Ge. The range of efficient emission is to 120° with the first band interaction, and above 400° on the second band interaction. Low defect concentration in Ge is achieved through chemical vapor deposition at high vacuum (~1x10-8 mbar) in a two-step...
We present theoretical modeling and experimental results of optical gain and lasing from tensile-... more We present theoretical modeling and experimental results of optical gain and lasing from tensile-strained, n+ Ge-on-Si at room temperature. Compatible with silicon CMOS, these devices are ideal for large-scale electronic-photonic integration on Si.
Optics Express, 2012
Broadband and anisotropic light emission from rare-earth doped tellurite thin films is demonstrat... more Broadband and anisotropic light emission from rare-earth doped tellurite thin films is demonstrated using Er 3+ -TeO 2 photonic crystals (PhCs). By adjusting the PhC parameters, photoluminescent light can be efficiently coupled into vertical surface emission or lateral waveguide propagation modes. Because of the flexibility of light projection direction, Er 3+ -TeO 2 is a potential broadband light source for integration with threedimensional photonic circuits and on-chip biochemical sensors.
CLEO:2011 - Laser Applications to Photonic Applications, 2011
For several decades, the performance of Si microprocessors has increased exponentially following ... more For several decades, the performance of Si microprocessors has increased exponentially following Moore's Law by scaling down the critical dimensions of transistors. However, over the last several years, microprocessor performance has not followed as expected trend from Moore's ...
Advanced Functional Materials, Mar 10, 2009
A series of push‐pull azo compounds containing bulky substituents are synthesized, yielding fully... more A series of push‐pull azo compounds containing bulky substituents are synthesized, yielding fully amorphous materials with glass‐transition temperatures above 200 °C. Thin films are subjected to holographic illumination and show superior bulk photomigration in terms of speed and efficiency compared to materials exhibiting similar electronic and photochromic properties in the solid state. The reported results give evidence that a microscopic consideration of the free volume rather than macroscopic parameters like the glass‐transition temperature should to be adopted to interpret the matrix stiffness and its deformation ability. Irradiation performed at higher laser intensity produces periodic superstructures whose height is five to six times as high as the initial film thickness. The surface tension and instability effects are put forward to interpret the growth of such superstructures.
ECS Meeting Abstracts, 2010
not Available.
Proceedings of SPIE, Feb 19, 2014
ABSTRACT Ge-on-Si devices are explored for photonic integration. Through the development of bette... more ABSTRACT Ge-on-Si devices are explored for photonic integration. Through the development of better growth techniques, monolithic integration, laser design and prototypes, it was possible to probe Ge light emitters with emphasis on lasers. Preliminary worked shows thermal photonic behavior capable of enhancing lamination at high temperatures. Increase luminescence is observed up to 120°C from L-band contribution. Higher temperatures show contribution from Δ -band. The increase carrier thermal contribution suggests high temperature applications for Ge light emitters. A Ge electrically pumped laser was probed under 0.2% biaxial strain and doping concentration ~4.5×1019cm-3 n-type. Ge pnn lasers exhibit a gain >1000cm-1 with 8mW power output, presenting a spectrum range of over 200nm, making Ge the ideal candidate for Si photonics. Large temperatures fluctuations and process limit the present device. Theoretically a gain of >4000cm- gain is possible with a threshold of as low as 1kA/cm2. Improvements in Ge work
Frontiers in Optics 2010/Laser Science XXVI, 2010
Monolithic lasers on silicon are ideal for large-scale, high volume electronic-photonic integrati... more Monolithic lasers on silicon are ideal for large-scale, high volume electronic-photonic integration for high performance and high-energy efficiency information technologies [1]. Germanium is a particularly interesting candidate due to its compatibility with Si-based complementary ...
Advanced Photonics, 2011
... Rodolfo Camacho-Aguilera1, Jonathan Bessette1, Yan Cai1, Xiaoman Duan1, Jifeng Liu2, Lionel K... more ... Rodolfo Camacho-Aguilera1, Jonathan Bessette1, Yan Cai1, Xiaoman Duan1, Jifeng Liu2, Lionel Kimerling1, Jurgen Michel1 1Massachusetts Institute of Technology, 77 Massachusetts Ave Cambridge, MA, 02139 2Thayer School of Engineering at Dartmouth College, 8000 ...
IEEE Journal of Selected Topics in Quantum Electronics, 2013
We analyze the optical gain of tensile-strained, n-germanium (n-Ge) material taking bandgap narro... more We analyze the optical gain of tensile-strained, n-germanium (n-Ge) material taking bandgap narrowing (BGN) for heavily doped Ge into account. Both the direct bandgap and indirect bandgap are narrowed by 60 meV. Our new modeling explains the wide lasing spectrum of 1520-1700 nm in electrically pumped Ge lasers. The calculated materials gain can reach 1000 cm-1 when the injected carrier density is ~mid-1019 cm-3 with a combination of 0.25% tensile strain and 4.5×1019 cm-3 n-type doping. The threshold current density is estimated to be 0.53 kA/cm2 for an optimized edge-emitting double-heterojunction Ge device, comparable to bulk III-V lasers. We also review current progress on Ge quantum-well (QW) structures. The threshold current density of most Ge QW structures is similar to bulk Ge. Only tensile-strained QWs show reduced threshold currents.
ECS Transactions, 2013
We study the phosphorous (P) diffusion in Ge grown on Si substrate with different background dopi... more We study the phosphorous (P) diffusion in Ge grown on Si substrate with different background doping and we find that the diffusion coefficient is extrinsic and is enhanced by over 500 times in Ge doped at 1x1019 cm-3 compared to diffusivity in intrinsic Ge. We study the loss mechanisms in Ge-on-Si. We show that the doping level is a result of the balance between in-diffusion and dopant loss. The high diffusivity in doped Ge leads to a uniform distribution of P in Ge with the concentration above 4.5x1019 cm-3.
Optics Express, 2012
Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demon... more Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demonstrated. Room temperature multimode laser with 1mW output power is measured. Phosphorous doping in Germanium at a concentration over 4x10 19 cm −3 is achieved. A Germanium gain spectrum of nearly 200nm is observed. integration of room-temperature cw GaAs/AlGaAs lasers on Si substrates via relaxed graded GeSi buffer layers," J. Appl. Phys. 93(1), 362-367 (2003). 3. H. Park, A. Fang, S. Kodama, and J. Bowers, "Hybrid silicon evanescent laser fabricated with a silicon waveguide and III-V offset quantum wells," Opt. Express 13(23), 9460-9464 (2005).
National Fiber Optic Engineers Conference, 2012
... Jurgen Michel1, Rodolfo E. Camacho-Aguilera1, Yan Cai1, Neil Patel1, Jonathan T. Bessette1, M... more ... Jurgen Michel1, Rodolfo E. Camacho-Aguilera1, Yan Cai1, Neil Patel1, Jonathan T. Bessette1, Marco Romagnoli1,2, Birendra (Raj) Dutt2,3, Lionel C. Kimerling1 1Massachusetts Institute of Technology, 77 Massachusetts Ave ... Page 2. secondary ion mass spectrometry (SIMS). ...
The 9th International Conference on Group IV Photonics (GFP), 2012
ABSTRACT CMOS Ge-on-Si pnn multimode laser diode is demonstrated. Calculated losses suggest a gai... more ABSTRACT CMOS Ge-on-Si pnn multimode laser diode is demonstrated. Calculated losses suggest a gain above 100cm-1. Observed power of above 1mW is reported.
Advanced Photonics Congress, 2012
ABSTRACT Germanium lasing from Ge-on-Si pnn heterojunction diode structures is demonstrated. Sele... more ABSTRACT Germanium lasing from Ge-on-Si pnn heterojunction diode structures is demonstrated. Selective growth of highly phosphorus doped Ge in oxide trenches shows a design for CMOS compatible laser integration.
Optics Express, 2012
Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demon... more Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demonstrated. Room temperature multimode laser with 1mW output power is measured. Phosphorous doping in Germanium at a concentration over 4x10 19 cm −3 is achieved. A Germanium gain spectrum of nearly 200nm is observed. integration of room-temperature cw GaAs/AlGaAs lasers on Si substrates via relaxed graded GeSi buffer layers," J. Appl. Phys. 93(1), 362-367 (2003). 3. H. Park, A. Fang, S. Kodama, and J. Bowers, "Hybrid silicon evanescent laser fabricated with a silicon waveguide and III-V offset quantum wells," Opt. Express 13(23), 9460-9464 (2005).
Optics Letters, 2010
Monolithic lasers on Si are ideal for high volume and large-scale electronic-photonic integration... more Monolithic lasers on Si are ideal for high volume and large-scale electronic-photonic integration. Ge is an interesting candidate due to its pseudo-direct gap properties and compatibility with Si complementary metal oxide semiconductor (CMOS) technology. Recently we have demonstrated room temperature photoluminescence, electroluminescence and optical gain from the direct gap transition of band-engineered Ge-on-Si using tensile strain and n-type doping. Here we report the first experimental observation of lasing from the direct gap transition of Ge-on-Si at room temperature using an edge emitting waveguide device. The emission exhibited a gain spectrum of 1590-1610 nm, line narrowing and polarization evolution from a mixed TE/TM to predominantly TE with increasing gain, and a clear threshold behavior.
Thin Solid Films, 2012
Electronic-photonic synergy has become an increasingly clear solution to enhance the bandwidth an... more Electronic-photonic synergy has become an increasingly clear solution to enhance the bandwidth and improve the energy efficiency of information systems. Monolithic integration of optoelectronic devices is the ideal solution for large-scale electronic-photonic synergy. Due to its pseudo-direct gap behavior in optoelectronic properties and compatibility with Si electronics, epitaxial Ge-on-Si has become an attractive solution for monolithic optoelectronics. In this paper we will review recent progress in Ge-on-Si optoelectronics, including photodetectors, electroabsorption modulators, and lasers. The performance of these devices has been enhanced by band-engineering such as tensile strain and n-type doping, which transforms Ge towards a direct gap material. Selective growth reduces defect density and facilitates monolithic integration at the same time. Ge-on-Si photodetectors have approached or exceeded the performance of their III-V counterparts, with bandwidth-efficiency product > 30 GHz for p-i-n photodiodes and bandwidth-gain product > 340 GHz for avalanche photodiodes. Enhanced Franz-Keldysh effect in tensile-strained Ge offers ultralow energy photonic modulation with b 30 fJ/bit energy consumption and > 100 GHz intrinsic bandwidth. Room temperature optically-pumped lasing as well as electroluminescence has also been achieved from the direct gap transition of band-engineered Ge-on-Si waveguides. These results indicate that band-engineered Ge-on-Si is promising to achieve monolithic active optoelectronic devices on a Si platform.
Ge-on-Si devices are explored for photonic integration. Importance of Ge in photonics has grown a... more Ge-on-Si devices are explored for photonic integration. Importance of Ge in photonics has grown and through techniques developed in our group we demonstrated low density of dislocations (<1x109cm-2) and point defects Ge growth for photonic devices. The focus of this document will be exclusively on Ge light emitters. Ge is an indirect band gap material that has shown the ability to act like a pseudo direct band gap material. Through the use of tensile strain and heavy doping, Ge exhibits properties thought exclusive of direct band gap materials. Dependence on temperature suggests strong interaction between indirect bands, [Delta] and L, and the direct band gap at [Gamma]. The behavior is justified through increase in photoluminescence on Ge. The range of efficient emission is to 120° with the first band interaction, and above 400° on the second band interaction. Low defect concentration in Ge is achieved through chemical vapor deposition at high vacuum (~1x10-8 mbar) in a two-step...
We present theoretical modeling and experimental results of optical gain and lasing from tensile-... more We present theoretical modeling and experimental results of optical gain and lasing from tensile-strained, n+ Ge-on-Si at room temperature. Compatible with silicon CMOS, these devices are ideal for large-scale electronic-photonic integration on Si.
Optics Express, 2012
Broadband and anisotropic light emission from rare-earth doped tellurite thin films is demonstrat... more Broadband and anisotropic light emission from rare-earth doped tellurite thin films is demonstrated using Er 3+ -TeO 2 photonic crystals (PhCs). By adjusting the PhC parameters, photoluminescent light can be efficiently coupled into vertical surface emission or lateral waveguide propagation modes. Because of the flexibility of light projection direction, Er 3+ -TeO 2 is a potential broadband light source for integration with threedimensional photonic circuits and on-chip biochemical sensors.
CLEO:2011 - Laser Applications to Photonic Applications, 2011
For several decades, the performance of Si microprocessors has increased exponentially following ... more For several decades, the performance of Si microprocessors has increased exponentially following Moore's Law by scaling down the critical dimensions of transistors. However, over the last several years, microprocessor performance has not followed as expected trend from Moore's ...