About

Professor Can Bayram is a Principal Investigator at ICORLAB, Illinois. He holds a Ph.D. degree in Electrical Engineering from Northwestern University, IL, USA. He also earned his M.S. degree in Electrical Engineering and his B.S. degree in Electrical Engineering and Physics from Georgia Institute of Technology, GA, USA. Professor Bayram originates from Izmir, Turkey. The information provided highlights his academic background and current role but does not include specific details about his research focus or key contributions.

Research topics

• Optoelectronics
• Materials science
• Physics
• Electrical engineering
• Nanotechnology
• Engineering
• Composite material
• Condensed matter physics
• Computational chemistry
• Chemistry

Selected publications

• Ultrafast vertical photoconductive intrinsic diamond switch with high current (17.1 A at 1 kV)

  Applied Physics Letters · 2026-03-23

  articleSenior author

  This Letter reports on a vertical, bulk-conducting photoconductive semiconductor switch (PCSS) fabricated on an intrinsic Type IIa single-crystal diamond substrate. Under near-bandgap excitation at 225 nm with a 20 μJ pulse, a strong photocurrent response of 17.1 A at 1 kV DC bias magnitude is obtained by (i) tuning the optical trigger wavelength to the “matched-absorption” window (224–235 nm) near the band edge, where the optical penetration depth becomes comparable to the 500 μm substrate thickness, and (ii) choosing the bias polarity ensuring electron-dominant conduction, given that electrons have a higher mobility than holes in diamond. The PCSS has an area-normalized responsivity of 54.2 mA W−1 cm−2 and an effective on-resistance of 8.48 Ω, with a fast 90%–10% transient fall time of 25 ns, attributed to carrier sweep-out. These results support vertical, bulk-conducting intrinsic diamond PCSS as a promising platform for high-power optical switching and provide new insight into intrinsic photoconductivity in diamond.

  PublisherDOI

• Efficiency droop contributors in InGaN green light emitting diodes

  Applied Physics Letters · 2025-05-26 · 1 citations

  articleSenior author

  Here, efficiency droop contributors (i.e., inherent Auger–Meitner recombination, polarization-induced effects, thermal effects, and light extraction) in InGaN green light emitting diodes (LEDs) are decoupled and quantified. First, a modified ABC model is developed, and external quantum efficiency measurements are taken under constant and pulsed currents (EQEConstant and EQEPulsed, respectively). The LED internal quantum efficiency with and without thermal effects (IQEConstantABC and IQEPulsedABC, respectively) is extracted using the modified model. Then, using Raman spectroscopy, the LED junction temperature is extracted. Finally, using the optical-electrical model (OEM), the polarization- and temperature-independent LED internal quantum efficiency (IQEOEM) is calculated from the modified ABC model and the extracted junction temperature. By comparing external (EQEConstant) and the three internal quantum efficiencies (IQEConstantABC, IQEPulsedABC, and IQEOEM), the impacts of inherent Auger–Meitner recombination, polarization-induced effects, thermal effects, and light extraction on the efficiency droop are decoupled and quantified. It is found that inherent Auger–Meitner recombination-induced droop is approximately 49% of the total efficiency droop in commercial green LEDs, while polarization-induced effects contribute about 35%, and thermal droop accounts for nearly 16%. These findings suggest, to quash the green gap, it is critical to search for materials and device designs with low inherent Auger–Meitner coefficients and polarization fields, respectively.

  PublisherDOI

• Top-down fabrication of InGaN-based nano light-emitting diodes

  2025-03-21

  articleSenior author

  Micro/Nano light emitting diodes (LEDs) have become front-runners for next-generation display architectures compared to organic LED (OLED) and liquid crystal displays in part due to their superior performance. Their versatility has led to additional applications in visible light communications (VLC), sensing and optogenetics. Despite potential benefits of smaller devices, there have been limited efforts in demonstrating sub-micron LEDs due to challenges in scaling fabrication techniques from large area LEDs. In this work, first, we demonstrate a top-down fabrication process using electron beam lithography where nano-LEDs with mesa sizes down to 250nm were fabricated. Then, the optical properties of the nano- LEDs are studied. Spectral properties as a function of injection current density from 1.6Acm^-2 to 240Acm^-2were measured showing minimum variation in FWHM of approximately 20nm and invariant peak wavelength of approximately 439nm from 24Acm^-2 to 240Acm^-2. Spatially resolved optical properties were studied via micro-electroluminescence mapping and confocal microscopy demonstrating sub-micron spatial emission profile width of approximately 800 nm. This work shows the potential of nano LEDs as a suitable technology for next generation displays and advanced light engines.

  PublisherDOI

• Record performance in intrinsic, impurity-free lateral diamond photoconductive semiconductor switches

  Applied Physics Letters · 2025-04-01 · 7 citations

  articleOpen accessSenior author

  Photoconductive semiconductor switches (PCSSs) are fabricated on type IIa diamond substrates with varying boron and nitrogen impurity levels (<1014–1016 cm−3). The photoresponse of lateral PCSS is reported over the incident laser wavelength range (212–240 nm), energy per pulse (5–65 μJ), and DC bias (−1.2 to +1.2 kV). The PCSS device with the lowest boron and nitrogen impurity concentration achieves the highest normalized responsivity of 9.1 × 10−8 A-cm/W-V, peak photocurrent of 8.0 A, and on/off ratio of 2.3 × 1011 at a DC bias of +1.2 kV with the potential for even higher currents at increased DC bias. All PCSS display fast rise times (<3 ns), limited by the laser's rise time. However, photoresponse measurements reveal that higher impurity levels reduce the photocurrent and decrease the on/off ratio. These results highlight the performance advantages of using low background concentration type IIa diamond substrates for PCSS fabrication and present a promising route toward advanced high-power, high-speed diamond-based switches.

  PublisherDOI

• Green Light Emitting Diodes for the Ultimate Solid-state Lighting

  2025-08-08

  reportOpen access1st authorCorresponding

  Light-emitting diodes (LEDs), in particular InGaN-based LED devices, have achieved remarkable success in solid-state lighting, contributing to 25% of energy savings already. However, more than two thirds of the electricity is still lost as heat in current white LEDs today. Furthermore, expected population growth and increasing demand for lighting necessitate a more efficient approach, which can only be realized by solving the issue of the green gap (i.e., the inefficiency of the state-of-the-art green LEDs). This green gap is a fundamentally limiting issue in conventional hexagonal nitride LEDs, leading to 19% wall-plug efficiency (WPE) at 100 A/cm2, while the department of energy goal is 30% (in 2025) and 55% (in 2035). Novel cubic nitride LEDs are proposed as a promising solution to the green gap, tripling the efficiency with 30% less indium required in the green and beyond spectrum, due to well- documented advantages in literature. However, there are theoretical and experimental issues in the current approach that need to be innovated in order to translate these material advantages into functional devices and address the green gap with the cubic nitride approach. In this project, the realization of cubic nitride LEDs was attempted targeting a WPE of ≥ 50% under injection current density of ≥ 100 A/cm2 and at a junction temperature of ≤ 85°C. The project adds significant number of new insights on cubic nitride LEDs, including (i) a method to synthesize phase-pure low-defect-density cubic gallium nitride (GaN), (ii) high-efficiency cubic green LED design rules, (iii) revised material parameters that were misunderstood for over twenty years, and (iv) scaling down and enabling (sub)-micron cubic nitride devices. The effectiveness of the technology is proved by the demonstration of efficiency six times higher than conventional cubic nitride technologies, while economic feasibility is demonstrated via the patterned silicon (100) substrate fabrication from a commercial CMOS foundry. The project also gives insight into achieving high speed, high-efficiency light sources by scaling down the devices, potentially usable for optical communication, and achieving cubic nitride power electronics, for true CMOS-compatible GaN devices.

  PublisherOA PDFDOI

• Cubic GaN: Growth, Characterization, and Applications

  ˜The œMaterials Research Society series · 2025-01-01

  book-chapterSenior author
  PublisherDOI

• Efficiency cliff in scaling InGaN light-emitting diodes down to submicron

  Applied Physics Letters · 2025-06-16 · 3 citations

  articleSenior author

  The top-down submicron fabrication of blue-emitting light-emitting diodes on Qromis Substrate Technology substrates is reported. Light-emitting diodes with mesa sizes as small as 250 × 250 nm2 show ideal forward voltage and low leakage current density. It is observed that sidewall treatment and passivation methods used in micro-light-emitting diodes (2–20 μm) do not lead to the same level of sidewall recombination suppression for submicron ones (<1 μm), as evidenced by a ∼70% decrease in peak external quantum efficiencies when mesa sizes are scaled from 2 μm down to 250 nm. This is attributed to the lateral carrier diffusion being comparable to the mesa size, regardless of the sidewall passivation and recovery. The results call for rethinking the impact of sidewalls in emerging top-down fabricated (sub)micrometer-light-emitting diodes.

  PublisherDOI

• Green-emitting cubic GaN/In0.16Ga0.84N/GaN quantum well with 32% internal quantum efficiency at room temperature

  Applied Physics Letters · 2024-01-01 · 8 citations

  articleOpen accessSenior author

  Structural and optical properties of a green-emitting cubic (i.e., zinc blende) GaN/In0.16Ga0.84N/GaN single quantum well structure are reported. The active layer is grown on a phase-pure (i.e., 100%) cubic GaN enabled on a 1 × 1 cm2 U-grooved silicon (100) through aspect ratio phase trapping. Energy dispersive x-ray spectroscopy combined with room temperature cathodoluminescence reveals 522 nm green light emission at room temperature with only 16.0% ± 1.6% of indium content, which is ∼30% less than the amount of indium needed in a traditional green-emitting hexagonal (i.e., wurtzite) well. Temperature-dependent behavior of the green emission, such as activation energy, s-shaped peak energy shift, and linewidth, is reported. Cathodoluminescence at 8 and 300 K reveals an internal quantum efficiency of 32.0% ± 0.6%, which is higher than any reported value for cubic wells. Overall, phase-pure cubic active layers on phase transition cubic GaN are shown to be promising for green and longer wavelength emitters.

  PublisherOA PDFDOI

• Thin film development for LED technologies

  Elsevier eBooks · 2024-10-18 · 1 citations

  book-chapterSenior author
  PublisherDOI

• Contributors

  Elsevier eBooks · 2024-10-18

  book-chapterOpen access
  PublisherDOI

Recent grants

• CAREER: Cubic Phase Green Light Emitting Diodes for Advanced Solid State Lighting

  NSF · $548k · 2017–2022

Frequent coauthors

• Manijeh Razeghi

  105 shared

• Ryan McClintock

  Northwestern University

  66 shared

• W Nehrer

  University of Cambridge

  44 shared

• Benjamı́n Iñı́guez

  Universidad Rovira i Virgili

  44 shared

• Mario Lanza

  44 shared

• C Velez

  Exalos (Switzerland)

  44 shared

• Joachim N. Burghartz

  Institut für Mikroelektronik Stuttgart

  44 shared

• John M. Dallesasse

  University of Illinois Urbana-Champaign

  44 shared

Labs

• ICORLABPI

Awards & honors

• International Union of Pure and Applied Physics Young Scient…
• IEEE Nanotechnology Council Early Career Award (2018)
• IEEE Electron Devices Society Early Career Award (2018)
• NSF CAREER & AFOSR Young Investigator Awards (2017)
• SPIE Fellow (2025)