Achievements

International Conference on Solar Energy Photovoltaic (ICSEP 2025) during 18 - 21 December 2025 at KIIT Deemed to be University, Bhubaneswar, India, organized by Prof. U. P. Singh School of Electronics.

• Optical and Electrical Interpretation of GaAs Thin-film Deposited by Magnetron Sputtering (Oral presentation)

The work deposits GaAs thin films via RF magnetron sputtering by varying the duration and substrate temperature. The X-ray diffraction patterns analyze the crystallinity of the films. A single broad Raman peak at ~ 265 cm-1 shows the amorphous nature of the as-sputtered GaAs films, regardless of the deposition duration and the substrate temperature. The broad photoluminescence peak around ~ 885 nm confirms the band gap of the GaAs as ~ 1.4 eV (also supported by the band gap obtained from the UV-Visible spectroscopy), and deconvolution of the peaks represents the other possible crystalline structures.

• Electrical and Optical Coupling Analysis of Two-terminal and Four-terminal InGaP//SiNW Tandem Photovoltaic Efficiency (Poster presentation)

The balanced composition (In0.5Ga0.5P) with a wide band gap of 1.9 eV acts as the top cell, whereas the Si-Si nanowire (SiNW) heterojunction cell acts as the bottom cell. The subcells share the complementary portions of the solar spectrum. The introduction of the SiNW array (band gap of 1.57 eV compared to the 1.12 eV of bulk-Si) as the emitter of the bottom cell increases the photon absorption and widens the external quantum efficiency band. The work simulates the InGaP//SiNW tandem architecture using the SCAPS-1D by considering the experimentally achieved SiNW array parameters. 

International Conference on Laser & other Deposition Techniques (iCOLD - 2025) during 06 - 08 March 2025 at
Indian  Institute of  Technology Hyderabad, Telangana, India
Organized by Prof. Ranjith Ramadurai from Dept. of Materials Science And Metallurgical Engineering

Design of InGaP//GaAs Thin-film Tandem Solar Cell Architecture for Challenging Environments   (Oral Presentation), Available publication: IOP, Journal of Physics D: Applied Physics

The power conversion efficiency of the single junction solar cell is approaching the theoretical limits, which leads to the development of tandem cells. Among various solar cell materials, compound semiconductors such as GaAs and InGaP are the large band gap materials preferred for multijunction solar cells. Besides the broad-spectrum absorption, GaAs and InGaP possess high temperature stability, radiation resistance, longer minority carrier lifetime, and higher electron mobilities compared to the widely used Si for photovoltaics. The work reports the simulated InGaP//GaAs thin film tandem cell architectures to enhance the overall cell efficiency.

Advances in Sustainable Solutions for Energy Transitions (ASSET - 2025) during 02 - 04 January 2025 at
Indian  Institute of  Technology Guwahati, Assam, India
Organized by Prof. Vaibhav V. Goud School of Energy Science and Engineering

Analysis of Capacitance-Voltage Measurements for Majority Carrier Depth Profiling of Phosphorus-doped Si Nanowire  (Oral Presentation),
Available publication: Springer Conference Proceeding Book Chapter

Doping depth profile measurement for Si is essential for determining junction depth, leakage current, threshold current, and overall device parameters. However, the widely used sophisticated approaches such as secondary ion mass spectroscopy and electrochemical capacitance-voltage (ECV) measurement are destructive techniques. Further, these techniques are not preferred for doping measurement of Si nanostructures, especially Si nanowires (SiNWs), due to complex multidimensional depth profiling. The work utilizes non-destructive majority-carrier depth profile analysis of the SiNW array using dry capacitance-voltage (CV) measurement and addresses the oxide layer and air-gap issues. A boron-doped p-type SiNW array was fabricated by pre-optimized metal-assisted chemical etching. SiNW array was doped with P by spin-on-doping (spin-coating of P-containing phosphosilicate glass sol-gel followed by annealing), varying the P-concentration. P-concentration was varied in the sol-gel by varying the P2O5 concentration to 1.25 mM, 2.5 mM, 5.0 mM, and 7.5 mM. 

Power India International Conference (PIICON-2024) at
Malaviya National Institute of Technology Jaipur, Rajasthan
2024 IEEE 11th Power India International Conference (PIICON 2024), under the aegis of IEEE Delhi Section, IEEE Industry Applications Society, IEEE Power Electronics Society as Technical Co-sponsors and IEEE Delhi Section PES/IA Joint Chapter, is the premier conference for sharing cutting-edge research, theories, and practices with various industry sectors. 

Introduction of Si-nanowire in Four-terminal (4T) Tandem Solar Cell to Improve Efficiency Share  (Oral Presentation), It will be published in IEEE Xplore

The main challenge in commercializing multi-junction tandem solar cells is the lack of economic viability, primarily due to the poor performance of the bottom cell caused by optical coupling. The study introduces a Si-nanowire (SiNW) array as the bottom cell of a GaAs//Si-nanowire tandem architecture to enhance the efficiency of the bottom cell in a four-terminal (4T) configuration. The work compares the bulk Si cell and SiNW for the bottom cell. Simulations of the SiNW bottom cell incorporate two key features from experimental data: increased surface area for improved photon absorption and increased surface recombination. Enhanced photon absorption in the SiNW array allows it to utilize the filtered spectra from the GaAs top cell, boosting the efficiency share and making the tandem architecture more cost-effective. The SiNW bottom cell shares 40.5% of the 4T tandem efficiency (30.85%).

Advanced Nano Materials (ANM-2024) at the University of Aveiro, Portugal, 21st ANM (2024) was organized from 23rd – 26th July 2024. Organizer: Prof. João Campos Gil, Dr. Elby Titus, Prof. Luiz Fernando Ribeiro Pereira

Modified Silicon Nanowire Fabrication and Annealing Temperature Optimization for Improving Solar Cell Efficiency (Oral Presentation), 
Journals available for publication IJHE (IF 8.2) and Energy Storage (3.4)

The work employs cost-effective pre-optimized metal-assisted chemical etching (MACE) parameters for p-type SiNW array fabrication and spin-on-doping with P2O5 as the P-source by phosphosilicate glass (PSG) layer formation to form an n-type emitter. A Teflon-lined stainless-steel MACE setup was used for the SiNW array fabrication to avoid the unwanted SiNW formation on the rear side of the Si substrate. The annealing temperature was optimized considering the doping diffusion depth and the oxidation layer on the inner surface of the nanopores of the SiNW tips. Annealing above 900 ºC causes oxidation on SiNW tips, leading to tip dissolution during PSG layer removal, shortening SiNW length, and widening of the bandgap.

International Meeting on Energy Storage Devices (IMESD-2023), 2nd IMESD (2023) was organized at IIT Roorkee, Uttarakhand, from 7th – 12th December 2023. Organizing head: Prof. Yogesh Sharma,  Department of Physics

Interface engineering of metal-coated Si-nanostructure thin films for High-capacity Li-ion battery anode (Poster presentation),
later assigned to ASC Energy and Fuels (IF 3.7)

This study explores the surface engineering of ultrathin (≤ 5 nm) Ag and Cu coating on PS and SiNW array thin films made via electrochemical anodization and metal-assisted chemical etching for the anode. The morphology of the metal coatings was analyzed using electron microscopy with focused ion beam preparation of lamellae. Grazing-incidence X-ray diffraction analyzed metal phases, while X-ray reflectivity with critical angle measurement determined the thickness, density, and roughness of deposited thin film interfaces.

International Symposium on Semiconductor Materials and Devices (ISSMD-2022), organized by the Semiconductor Society of India (SSI) at KIIT University, Bhubaneswar, Odisha, India, from 16th – 18th December 2022. Organizing head: Prof. Udai Pratap Singh

Tailoring electrical characteristics of Si-nanowires and etched Si by MACE temperature variation (Poster presentation),
Published in the Journal of Materials Science: Materials in Electronics (IF 2.8)

Optoelectronic applications prefer Si nanostructures over bulk Si due to improved optical and electrical properties. However, tuning the electrical properties of Si nanostructures is a bottleneck for a broad range of applications. Metal-assisted chemical etching (MACE) is a cost-effective method to fabricate silicon nanowires (SiNWs) array and etched silicon (eSi) using bulk-Si and porous substrates, respectively. Among various fabrication parameters, MACE temperature is appropriate to tailor the nanostructure dimensions- length and diameter of SiNWs and thickness of the porous layer of eSi, on which the bandgap and the electrical biasing characteristic depend. The study addresses the dimensional change of nanostructures as the impact of MACE temperature variation on the bandgap and the DC bias characteristics. Increasing MACE temperature reduces the nanowire diameter and the porous layer thickness. As a result, the bandgap widening and the lowering of the DC bias current are characterized by the series diode-resistance equivalent circuits.

Best Paper Award in Power India International Conference (PIICON-2024) at MNIT Jaipur, Rajasthan 

Theme: Power conversion, transmission, and utilization

Title: Introduction of Si-nanowire in Four-terminal (4T) Tandem Solar Cell to Improve Efficiency Share  (Oral Presentation)

Samsung Fellowship for certification program on India Semiconductor Workforce Development Program (ISWDP) for Sentaurus TCAD organized by Indian Institute of Science Bangalore along with Synopsys and Samsung 

Theme: Level 1 for Semiconductor basics and TCAD introduction