Balaji Manavaimaran
@unom.ac.in
Assistant Professor, Department of Materials Science
University of Madras
Scopus Publications
Scopus Publications
Wolfhard Oberhausen, Iaroslav Lubianskii, Gerhard Boehm, Axel Strömberg, Balaji Manavaimaran, Dominik Burghart, Yan-Ting Sun, and Mikhail A. Belkin
AIP Publishing
Terahertz quantum cascade laser sources based on intra-cavity Cherenkov difference-frequency generation in dual-wavelength mid-infrared quantum cascade lasers are currently the only monolithic semiconductor laser technology that can deliver continuous-wave coherent terahertz output at room temperature. Because the Cherenkov difference-frequency generation process enables terahertz radiation generation and extraction across a wide range of frequencies, it is often assumed that phase-matching conditions for this process are automatically fulfilled. We theoretically analyze and experimentally demonstrate that phase-matching plays an important role in these devices, and significant improvements in terahertz power output can be achieved by adjusting the waveguide configuration of the quantum cascade lasers to provide better phase-matching.
Axel Strömberg, Balaji Manavaimaran, Lakshman Srinivasan, Sebastian Lourdudoss, and Yan-Ting Sun
Wiley
GaAsP/Si with high crystalline quality fabricated by cost‐effective heteroepitaxial technology is a promising pathway for realizing low‐cost Si‐based tandem solar cell with efficiency higher than 30%. Herein, hydride vapor‐phase epitaxy is used to perform selective area growth of GaAsP with high lateral coverage, referred to as epitaxial lateral overgrowth (ELOG). The ELOG is performed on GaAs‐based substrates as a prestudy, followed by GaAs/Si and GaAsP/Si seed wafers employing chemical mechanical polishing to fabricate full 2″ GaAsP/Si templates. These are subsequently used to grow and process GaAsP/Si pn‐junction structures for electrical characterization. The ELOG GaAsP is studied by spatially resolved photoluminescence (PL) mapping and high‐resolution X‐ray diffraction measurements. PL analysis of the GaAsP/GaAs ELOG samples reveals an enhanced P‐incorporation during lateral growth of GaAsP. This is also observed for the GaAsP/Si ELOG templates along with evidence of improved material quality, clearly distinguishing the laterally grown GaAsP from the planar growth directly above the Si substrate. Leakage pathways causing reduced electrical performance of the ELOG GaAsP/Si pn‐junction structures are identified.
Balaji Manavaimaran, Axel Strömberg, Vladimir L. Tassev, Shivashankar R. Vangala, Myriam Bailly, Arnaud Grisard, Bruno Gérard, Sebastian Lourdudoss, and Yan-Ting Sun
MDPI AG
Orientation-patterned gallium phosphide (OP-GaP) has been grown heteroepitaxially on OP gallium arsenide (GaAs) templates using hydride vapor phase epitaxy (HVPE). The effect of OP-GaAs template fabrication methods of epitaxial-inversion and wafer bonding on the heteroepitaxial OP-GaP growth has been investigated. OP-GaP layers with a growth rate of up to 35 µm/h and excellent domain fidelity were obtained. The growth rate and the domain fidelity have been revealed/studied by scanning electron microscope (SEM). In addition, we demonstrate that the crystalline quality of the individual domains, namely, the substrate-oriented domains (ODs) and the inverted domains (IDs), can be investigated by high-resolution x-ray diffraction reciprocal space mapping (HRXRDRSM), which can also indicate the domain fidelity. Attempts to increase the growth rate and improve the domain fidelity by increasing the III and V group precursors resulted in either an increase in the growth rate in the OP-GaP layers grown on epitaxial inversion OP-GaAs template at the expense of the domain crystalline quality and fidelity or an improvement in the crystalline quality of the domains at the expense of the growth rate in the OP-GaP layers grown on wafer-bonded OP-GaAs templates. In the case of OP-GaP grown on OP-GaAs templates prepared by epitaxial inversion, the crystalline quality of the ODs is better than that of the IDs, but it shows that the quality of the inverted layer in the template influences the quality and fidelity of the grown domains. To the authors’ knowledge, exploitation of HRXRDRSM studies on OP-GaP to establish the crystalline quality of its individual domains (ODs and IDs) is the first of its kind. OP-ZnSe grown on OP-GaAs templates has also been included in this study to further emphasize the potential of this method. We propose from this study that once the growth rate is optimized from SEM studies, HRXRDRSM analysis alone can be used to assess the structural quality and to infer the domain fidelity of the OP structures.
Ramarajan Ramanathan, Selvakumar Nagarajan, Surya Sathiyamoorthy, Balaji Manavaimaran, Harish C. Barshilia, and Ramesh Chandra Mallik
Royal Society of Chemistry (RSC)
Spray deposited Sb doped SnO2 thin film for room temperature ethanol gas detection.
Axel Strömberg, Balaji Manavaimaran, Xiaodan Pang, Richard Schatz, Oskars Ozolins, Sebastian Lourdudoss, David Stark, Mattias Beck, Giacomo Scalari, Jérôme Faist,et al.
SPIE
Buried heterostructure quantum cascade lasers (BH-QCLs) operating at high temperature in mid-infrared (MIR) to THz spectral range are desired for chemical sensing and free-space optical communication (FOC). In this work, Fe doped semi-insulating InP (SI-InP) regrowth is demonstrated in a hydride vapor phase epitaxy (HVPE) reactor for advanced MIR and THz BH-QCLs grown by MBE and MOCVD. SI-InP regrowth is implemented in THz QCL pillar arrays and narrow width and reverse-taper MIR BH-QCLs for efficient heat dissipation. By exploiting SI-InP regrowth, the parasitic capacitance in MIR distributed feedback BH-QCL can be suppressed, which is exploited for high speed FOC application.
Axel Strömberg, Yanqi Yuan, Feng Li, Balaji Manavaimaran, Sebastian Lourdudoss, Peng Zhang, and Yanting Sun
MDPI AG
Heteroepitaxial Zn-doped p-GaP was grown on (001) GaAs, (001) Si and (111) Si substrates by hydride vapor phase epitaxy for solar-driven photoelectrochemical applications of hydrogen generation by water splitting and CO2 reduction. Growth of GaP on Si was realized through the implementation of a low-temperature buffer layer, and the morphology and crystalline quality were enhanced by optimizing the precursor flows and pre-heating ambient substrate. The p-GaP/GaAs and p-GaP/Si samples were processed to photoelectrodes with an amorphous TiO2 coating for CO2 reduction and a combination of TiO2 layer and mesoporous tungsten phosphide catalyst for water splitting. P-GaP/GaAs with suitable Zn-doping concentration exhibited photoelectrochemical performance comparable to homoepitaxial p-GaP/GaP for water splitting and CO2 reduction. Degradation of photocurrent in p-GaP/Si photoelectrodes is observed in PEC water splitting due to the high density of defects arising from heteroepitaxial growth.
K. Prabakaran, R. Ramesh, P. Arivazhagan, M. Jayasakthi, S. Sanjay, S. Surender, I. Davis Jacob, M. Balaji, and K. Baskar
Elsevier BV
Balaji Manavaimaran and Sivasankaran B. Ravichandran
Wiley
Gallium nitride (GaN) and indium gallium nitride (InGaN) nanostructures, and their nanocomposites with reduced graphene oxide (rGO) are prepared by solvothermal method and used as sensing materials for ammonia gas. The ammonia sensing characteristics are studied by coating the synthesized GaN and InGaN nanostructures, and their nanocomposites on interdigitated electrodes. The sensing parameters, i.e., sensing response, selectivity, and stability, are studied for various operating temperatures and relative humidity. The pristine GaN and InGaN exhibit a sensing response of 23.8% and 28.1% for 200 ppm concentration at 300 K, whereas the nanocomposites of GaN and InGaN show an increased response of 37.4% and 44.2%. This improvement in the nanocomposites maybe ascribed to the better conductivity, higher number of gas adsorption sites and reduced bandgap. It is found that these materials are an excellent choice for ammonia gas sensing application.
A. Stromberg, B. Manavaimaran, L. Srinivasan, S. Lourdudoss, and Y.T. Sun
IEEE
High crystal quality GaAsP/Si fabricated by cost effective heteroepitaxial technology is promising to realize low-cost Si based tandem solar cell with efficiency higher than 30%. In this work, epitaxial lateral overgrowth (ELOG) of GaAsP/GaAs and GaAsP/GaAs/Si by hydride vapor phase epitaxy (HVPE) and their properties are studied by photoluminescence (PL) mapping. High crystal quality ELOG GaAsP/Si is obtained with enhanced PL intensity and narrow line width indicating reduced defect density provided by ELOG approach.
B.R. Sivasankaran and M. Balaji
Elsevier BV
K. Prabakaran, R. Ramesh, P. Arivazhagan, M. Jayasakthi, S. Sanjay, S. Surender, S. Pradeep, M. Balaji, and K. Baskar
Elsevier BV
K. Prabakaran, M. Jayasakthi, S. Surender, S. Pradeep, S. Sanjay, R. Ramesh, M. Balaji, Nicolas Gautier, and K. Baskar
Elsevier BV
K. Prabakaran, M. Jayasakthi, S. Surender, S. Pradeep, S. Sanjay, R. Ramesh, M. Balaji, and K. Baskar
Springer Science and Business Media LLC
Kandasamy Prabakaran, Subburaj Surender, Siddham Pradeep, Sankaranarayanan Sanjay, Madhaiyan Jayasakthi, Raju Ramesh, Eric Faulques, Manavaimaran Balaji, Shubra Singh, and Krishnan Baskar
Springer International Publishing
Prabakaran K., Jayasakthi M., Surender S., Pradeep S., Sanjay S., Ramesh R., Balaji M., and Baskar K.
Elsevier BV
K. Prabakaran, R. Ramesh, M. Jayasakthi, S. Surender, S. Pradeep, M. Balaji, K. Asokan, and K. Baskar
Elsevier BV
P. Arivazhagan, R. Ramesh, M. Balaji, K. Asokan, and K. Baskar
Elsevier BV
Romain Peretti, Valeria Liverini, Martin J. Süess, Yong Liang, Pierre- Baptiste Vigneron, Johanna M. Wolf, Christopher Bonzon, Alfredo Bismuto, Wondwosen Metaferia, Manavaimaran Balaji,et al.
Wiley
High power single mode quantum cascade lasers with a narrow far field are important for several applications including surgery or military countermeasure. Existing technologies suffer from drawbacks such as operation temperature and scalability. In this paper we introduce a fabrication approach that potentially solves simultaneously these remaining limitations. We demonstrate and characterize deep etched, buried photonic crystal quantum cascade lasers emitting around a wavelength of 8.5 μm. The active region was dry etched before being regrown with semi‐insulating Fe:InP. This fabrication strategy results in a refractive index contrast of 10% allowing good photonic mode control, and simultaneously provides good thermal extraction during operation. Single mode emission with narrow far field pattern and peak powers up to 0.88 W at 263 K were recorded from the facet of the photonic crystal laser, and lasing operation was maintained up to room temperature. The lasing modes emitted from square photonic crystal mesas with a side length of 550μm, were identified as slow Bloch photonic crystal modes by means of three‐dimensional photonic simulations and measurements.
Y. Liang, R. Peretti, V. Liverini, M. J. Süess, P-B. Vigneron, J. M. Wolf, C. Bonzon, A. Bismuto, S. Lourdudoss, W. Metaferia,et al.
OSA
We demonstrate a buried-heterostructure photonic-crystal quantum cascade laser operating at room temperature. The large-area coherent lasing enabled an output peak power of 0.88 W at 263 K with single-mode behavior and narrow far field pattern.
Balaji Manavaimaran and Baskar Krishnan
Informa UK Limited
ABSTRACT Irradiation effects of 120 MeV silicon ion with the fluence of 5 × 1012 ions/cm2 at room temperature and low temperature (77 K) on AlGaN/GaN heterostructures have been studied to probe the radiation tolerance for space applications. XRD results explicitly showed there were no compositional changes and additional phase formation due to irradiation. Smooth surface with atomic steps and terrace features has been observed in the pristine sample; upon irradiation, the surface become rough with annihilated surface steps. Atomic force microscopy images depict the nano and micro structures formation for the silicon ion irradiated AlGaN/GaN samples at room temperature and low temperature (77 K), respectively. Photoluminescence measurements revealed the blue shift of AlGaN layer in the low temperature irradiated samples. Intensity of defect peaks around 2.5–3.2 eV increases for irradiated samples. Low temperature irradiation decreases the radiation tolerance and increases the defects and surface roughness of the AlGaN/GaN heterostructures.
Qiye Zheng, Honggyu Kim, Runyu Zhang, Mauro Sardela, Jianmin Zuo, Manavaimaran Balaji, Sebastian Lourdudoss, Yan-Ting Sun, and Paul V. Braun
AIP Publishing
Three-dimensional (3D) photonic crystals are one class of materials where epitaxy, and the resultant attractive electronic properties, would enable new functionalities for optoelectronic devices. Here we utilize self-assembled colloidal templates to fabricate epitaxially grown single crystal 3D mesostructured GaxIn1−xP (GaInP) semiconductor photonic crystals using hydride vapor phase epitaxy (HVPE). The epitaxial relationship between the 3D GaInP and the substrate is preserved during the growth through the complex geometry of the template as confirmed by X-ray diffraction (XRD) and high resolution transmission electron microscopy. XRD reciprocal space mapping of the 3D epitaxial layer further demonstrates the film to be nearly fully relaxed with a negligible strain gradient. Fourier transform infrared spectroscopy reflection measurement indicates the optical properties of the photonic crystal which agree with finite difference time domain simulations. This work extends the scope of the very few known methods for the fabrication of epitaxial III-V 3D mesostructured materials to the well-developed HVPE technique.
R. Loganathan, M. Balaji, K. Prabakaran, R. Ramesh, M. Jayasakthi, P. Arivazhagan, Shubra Singh, and K. Baskar
Springer Science and Business Media LLC
R. Loganathan, R. Ramesh, M. Jayasakthi, K. Prabakaran, B. Kuppulingam, M. Sankaranarayanan, M. Balaji, P. Arivazhagan, Subra Singh, and K. Baskar
AIP Publishing LLC
Aluminum nitride (AlN) nanowalls have been epitaxially grown on dislocation assisted GaN/Al2O3 template by metal organic chemical vapor deposition (MOCVD) without any help of metal catalysts. A large number of nanowalls with thicknesses of 1.5-2.0 µm and height 400 nm have been deposited. The AlN nanowalls were found to have a preferred c-axis oriented with a hexagonal crystal structure. The AlN nanowalls and GaN/Al2O3 template have been characterize at room temperature photoluminescence (PL) and high resolution X-ray diffraction (HRXRD).
R. Ramesh, P. Arivazhagan, M. Balaji, K. Asokan, and K. Baskar
AIP Publishing LLC
In the present work, we have reported 100 MeV O{sup 7+} ion irradiation with 1×10{sup 12} and 5×10{sup 12} ions/cm{sup 2} fluence on AlGaN/GaN heterostructures grown on silicon substrate by Metal Organic Chemical Vapour Deposition (MOCVD). The Irradiated samples were characterized by High Resolution X-Ray Diffraction (HRXRD), Atomic Force Microscope (AFM) and Photoluminescence (PL). Crystalline quality has been analysed before and after irradiation using HRXRD. Different kinds of morphology are attributed to specific type of dislocations using the existing models available in the literature. A sharp band-edge emission in the as grown samples was observed at ∼3.4 eV in GaN and 3.82 for AlGaN. The band-edge absorption intensity reduced due to irradiation and these results have been discussed in view of the damage created by the incident ions. In general the effect of irradiation induced-damages were analysed as a function of material properties. A possible mechanism responsible for the observations has been discussed.
M. Balaji, R. Ramesh, P. Arivazhagan, M. Jayasakthi, R. Loganathan, K. Prabakaran, S. Suresh, S. Lourdudoss, and K. Baskar
Elsevier BV