Areas Of Work
Ultra-Wide Bandgap Oxide Semiconductors (β-Ga₂O₃ and r-GeO₂)

Thin Film Growth by Low-Pressure Chemical Vapor Deposition System:
Using a custom-designed LPCVD system, single-crystal β-Ga₂O₃ and r-GeO₂ thin films were successfully grown heteroepitaxially on substrates such as sapphire, SiC, and r-TiO₂. The overall structure of the growth system is shown in Figure 1. By obtaining sub-oxide vapors from elemental and compound solid sources, their transfer was achieved with argon, and growth on the substrate was realized in the presence of oxygen gas under suitable system pressure and growth temperature conditions.

Figure 1. Schematic design of the custom-built low-pressure chemical vapor deposition (LPCVD) system for oxide compounds

Power Electronics:

Power electronics is a field of engineering that studies the conversion, control, and efficient transmission of electrical energy. Its main objective is to convert electrical energy from one form to another with minimal losses. These conversions include processes such as AC to DC (rectification), DC to AC (inversion), DC to DC (switched-mode regulators), and AC to AC (frequency converters).

Major Sectors:

  • Energy and Power Systems: Renewable energy sources (solar panels, wind turbines) and integration into the electrical grid. Uninterruptible power supplies (UPS) and energy storage systems.
  • Transportation and Automotive: Motor drives in electric and hybrid vehicles, battery management systems, fast charging units. Speed control in railway and metro systems.
  • Industrial Automation: Motor drives in factories, robotic systems, high-power machine control circuits.
  • Aerospace and Defense: Power management in aircraft, radar and communication systems, energy control in military vehicles.
  • Electronic Devices and Consumer Electronics: Computer power supplies, phone chargers, LED lighting, household appliances.
  • Telecommunications: Base stations, signal amplifiers, energy management for data centers.
  • Healthcare Technologies: Energy control for medical imaging devices, laser systems, and precision measurement instruments.

    • Among the most common power electronic devices are diodes, thyristors, MOSFETs, and IGBTs. Diodes allow unidirectional current flow and are mainly used in rectifier circuits. Thyristors enable the control of AC current in high-power applications. MOSFETs are preferred in low- and medium-power applications due to their high switching speeds, while IGBTs are widely used in industrial systems that require high voltage and current.

    The main objective of our projects in this field is to achieve these devices with high efficiency on β-Ga₂O₃- and r-GeO₂-based thin-film semiconductors.

    Figure 2. Example geometry of a Schottky power diode.

    Solar-Blind Photodetectors:

    Solar-blind photodetectors are optoelectronic devices that are sensitive to light specifically in the ultraviolet (UV) region, but unresponsive to visible and infrared wavelengths. This property makes them “blind” to sunlight and enables a high signal-to-noise ratio. Since conventional photodetectors are sensitive to a broad spectrum, they struggle to accurately detect UV signals under the dominant influence of visible and infrared light. This often leads to false signals, particularly in outdoor applications with intense sunlight.

    Solar-blind photodetectors eliminate this problem by selectively detecting only UV light. In this way, reliability is enhanced in flame detection, early fire warning systems, biomedical imaging, environmental monitoring, and military applications. They also play a critical role in space research for measuring UV radiation in the upper layers of the atmosphere.

  • Fire and Safety Systems: Flame and spark detection, early fire warning systems.
  • Defense and Military Applications: Missile tracking, rocket motor flame detection, security sensors.
  • Space and Atmospheric Research: Measurement of solar radiation, UV monitoring in the upper atmosphere.
  • Environment and Industry: Detection of the ozone layer, air quality, and pollutants through UV monitoring.
  • Biomedical and Healthcare Technologies: UV-based sterilization monitoring, biological imaging, and diagnostic devices.
  • Energy and Power Systems: Arc detection in high-voltage power lines, safety applications in energy infrastructure

    • In general, they are designed in photoconductive, metal–semiconductor–metal (MSM), Schottky diode, and p–n junction structures. The devices operate by generating an electric current under light excitation, which is achieved through the absorption of UVC light that creates electron–hole pairs, subsequently drifted and collected at opposite electrodes.


    Figure 3. Example design of a vertical Schottky diode photodetector.

    Our Projects:

    In general, our completed and ongoing projects focus on the growth of single-crystal structures, n-/p-type doping, and the fabrication of basic power electronic and photodetector devices. In addition, we have projects currently in the proposal stage aimed at developing power electronic devices and solar-blind photodetectors.

    Completed and Ongoing Projects:

    As Principal Investigator:

  • TÜBİTAK 3501 Project (2019–2022): Growth of β-(AlₓInᵧGa(1-x-y))₂O₃ Layers by Low-Pressure Chemical Vapor Deposition (LPCVD) and Realization of Device Applications.
  • TÜBİTAK 1002 Project (2021–2022): Epitaxial Growth of Monoclinic Gallium Oxide (β-Ga₂O₃) Layers on 4H-Silicon Carbide (SiC).
  • TÜBİTAK 1001 Project (2022–2025): Growth and Characterization of Ultra-Wide Bandgap Rutile-GeO₂ Single-Crystal Structures by Low-Pressure Chemical Vapor Deposition (LPCVD).

    • As Researcher:

  • TÜBİTAK 1001 Project (2025–2027): Fabrication of Ge-Doped β-Ga₂O₃ Thin Films by RF Co-Sputtering and Their Application in Schottky Diodes.