Varsha Ashwin Vedaraj
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Varsha Ashwin Vedaraj has a total of 27 co-authors. Here are the top co-authors by number of shared publications:
- Kenneth B. Crozier
School of Physics, University of Melbourne, Parkville, Australia
3 shared publications - Alexander Corletto
School of Chemical and Biomedical Engineering Faculty of Engineering and Information Technology The University of Melbourne Parkville Victoria 3010 Australia
2 shared publications - James Bullock
Department of Electrical and Electronic Engineering University of Melbourne Victoria Australia
2 shared publications Jinyuan Chen
Department of Electrical and Electronic Engineering University of Melbourne Melbourne Victoria Australia
2 shared publicationsShifan Wang
Department of Electrical and Electronic Engineering University of Melbourne Victoria Australia
2 shared publications- Yuchen Sun
Department of Electrical and Electronic Engineering University of Melbourne Victoria Australia
2 shared publications
Latest Publications
- Open Access
- 20 September 2026
- Published by Wiley in Advanced Energy Materials
- p. e71599
Thermoradiative Diodes Using Black Phosphorus van der Waals Materials
The high radiative efficiencies and strong absorption coefficients of van der Waals materials position them well for optoelectronic power generation via radiative exchange. These materials have been investigated for use in solar cells, however, their use in thermoradiative and thermophotovoltaic applications in the mid‐infrared remains unexplored. We fabricate a black phosphorus ()/molybdenum disulfide () van der Waals heterojunction diode and use it in both thermoradiative and thermophotovoltaic operation modes. Open circuit voltage and short circuit current measurements taken as a function of temperature difference between the device and its environment, show the device can effectively generate power in both regimes. A net power density of is achieved at (thermoradiative), and at (thermophotovoltaic). This represents the first demonstration of thermoradiative power generation using van der Waals materials. Optoelectronic modeling further indicates that the performance is primarily limited by optical out‐coupling and external quantum efficiency. By addressing these, the short circuit current density could be increased by up to three orders of magnitude, corresponding to an approximate six orders of magnitude increase in power density.
- 20 September 2026
- Published by Wiley in Advanced Energy Materials
- p. e71599
Open AccessThermoradiative Diodes Using Black Phosphorus van der Waals Materials
The high radiative efficiencies and strong absorption coefficients of van der Waals materials position them well for optoelectronic power generation via radiative exchange. These materials have been investigated for use in solar cells, however, their use in thermoradiative and thermophotovoltaic applications in the mid‐infrared remains unexplored. We fabricate a black phosphorus ()/molybdenum disulfide () van der Waals heterojunction diode and use it in both thermoradiative and thermophotovoltaic operation modes. Open circuit voltage and short circuit current measurements taken as a function of temperature difference between the device and its environment, show the device can effectively generate power in both regimes. A net power density of is achieved at (thermoradiative), and at (thermophotovoltaic). This represents the first demonstration of thermoradiative power generation using van der Waals materials. Optoelectronic modeling further indicates that the performance is primarily limited by optical out‐coupling and external quantum efficiency. By addressing these, the short circuit current density could be increased by up to three orders of magnitude, corresponding to an approximate six orders of magnitude increase in power density.
- Open Access
Integration of Refractive Microlenses on BP/MoS 2 Photodiodes for Enhanced Infrared Photodetection
The van der Waals materials have emerged as promising candidates for infrared (IR) photodetectors. Among these, black phosphorus (BP)/ molybdenum disulphide (MoS 2 ) photodiodes have shown high specific detectivity at room‐temperature. The signal‐to‐noise performance of such detectors can be further improved by employing a microlens to increase the total photon collection without changing the device size, and hence its noise current. In this study, we explore the direct integration of refractive microlenses on BP/MoS 2 photodiodes, designed for operation at a wavelength of λ = 1.55 µm. The device's photoresponse is enhanced by up to 20× after microlens fabrication, enabling a detectivity of 1.83 × 10 9 cmHz 1/2 W −1 under zero‐bias at room‐temperature. Infrared imaging is achieved by integrating the device into a single‐pixel imaging set‐up. This enables a 255 × 192‐pixel image to be resolved from the transmission of a binary mask placed in front of a λ = 1.55 µm light source. These results demonstrate that direct integration of refractive microlenses with van der Waals photodiodes provides a simple and scalable route to enhance detectivity at room‐temperature, enabling practical near‐infrared computational imaging.
Open AccessIntegration of Refractive Microlenses on BP/MoS 2 Photodiodes for Enhanced Infrared Photodetection
The van der Waals materials have emerged as promising candidates for infrared (IR) photodetectors. Among these, black phosphorus (BP)/ molybdenum disulphide (MoS 2 ) photodiodes have shown high specific detectivity at room‐temperature. The signal‐to‐noise performance of such detectors can be further improved by employing a microlens to increase the total photon collection without changing the device size, and hence its noise current. In this study, we explore the direct integration of refractive microlenses on BP/MoS 2 photodiodes, designed for operation at a wavelength of λ = 1.55 µm. The device's photoresponse is enhanced by up to 20× after microlens fabrication, enabling a detectivity of 1.83 × 10 9 cmHz 1/2 W −1 under zero‐bias at room‐temperature. Infrared imaging is achieved by integrating the device into a single‐pixel imaging set‐up. This enables a 255 × 192‐pixel image to be resolved from the transmission of a binary mask placed in front of a λ = 1.55 µm light source. These results demonstrate that direct integration of refractive microlenses with van der Waals photodiodes provides a simple and scalable route to enhance detectivity at room‐temperature, enabling practical near‐infrared computational imaging.
- Open Access
- 3 July 2026
- Published by Springer Nature in Research Square
Hyperdoped silicon photodetectors enable room-temperature computational SWIR imaging at 1550 nm
Silicon’s bandgap inherently restricts its photodetection to wavelengths below 1100 nm, necessitating the integration of costly III-V semiconductors for short-wave infrared applications. Hyperdoping silicon beyond the solid solubility limit offers a promising “silicon-native” alternative, yet achieving practical short-wave infrared applications at room temperature remains a formidable challenge. Here, we demonstrate a high-detectivity hyperdoped silicon photodetector enabling room-temperature computational short-wave infrared imaging beyond Si bandgap wavelength at λ = 1550 nm. By integrating an ultrafast laser heating process step to reduce the dark current while keeping high responsivity, we achieve a specific detectivity \(\:{D}^{*}\) exceeding 10 9 Jones for 1550 nm at room temperature working in a forward-biased, photoconductive mode. The improved detectivity, coupled with a 59.4 dB linear dynamic range and kHz-scale bandwidth, allows us to demonstrate a single-pixel imaging system that reconstructs 1550 nm scenes at 65×63 pixels without cryogenic cooling. Our devices simultaneously support visible-light imaging, offering a path toward monolithically integrated, multispectral Si-native optical sensors. These results establish ultrafast-laser hyperdoped silicon as a viable platform for low-cost, room-temperature, short-wave infrared photonics, bridging the gap between advanced materials science and practical computational imaging system.- 3 July 2026
- Published by Springer Nature in Research Square
Open AccessHyperdoped silicon photodetectors enable room-temperature computational SWIR imaging at 1550 nm
Silicon’s bandgap inherently restricts its photodetection to wavelengths below 1100 nm, necessitating the integration of costly III-V semiconductors for short-wave infrared applications. Hyperdoping silicon beyond the solid solubility limit offers a promising “silicon-native” alternative, yet achieving practical short-wave infrared applications at room temperature remains a formidable challenge. Here, we demonstrate a high-detectivity hyperdoped silicon photodetector enabling room-temperature computational short-wave infrared imaging beyond Si bandgap wavelength at λ = 1550 nm. By integrating an ultrafast laser heating process step to reduce the dark current while keeping high responsivity, we achieve a specific detectivity \(\:{D}^{*}\) exceeding 10 9 Jones for 1550 nm at room temperature working in a forward-biased, photoconductive mode. The improved detectivity, coupled with a 59.4 dB linear dynamic range and kHz-scale bandwidth, allows us to demonstrate a single-pixel imaging system that reconstructs 1550 nm scenes at 65×63 pixels without cryogenic cooling. Our devices simultaneously support visible-light imaging, offering a path toward monolithically integrated, multispectral Si-native optical sensors. These results establish ultrafast-laser hyperdoped silicon as a viable platform for low-cost, room-temperature, short-wave infrared photonics, bridging the gap between advanced materials science and practical computational imaging system.