About

Dmitri Donetski is an Associate Professor at the Department of Electrical and Computer Engineering at Stony Brook University. His research focuses on the design of barrier photodetectors and the integration of photodetector arrays with front end electronics. His work involves developing advanced photodetection technologies and their electronic integration, contributing to the fields of optoelectronics and photonics.

Research topics

• Optoelectronics
• Optics
• Physics
• Materials science
• Condensed matter physics
• Nanotechnology
• Crystallography
• Chemistry
• Composite material
• Metallurgy

Selected publications

• Negative Photoconductivity in Ultranarrow-Gap Semiconductors

  Crystals · 2026-02-05

  articleOpen accessCorresponding

  A decrease in conductivity under illumination, known as negative photoconductivity, has been observed in various semiconductors and is commonly attributed to trapping of excess carriers by deep centers. Here, we demonstrate that negative photoconductivity can instead arise from a rapid increase in carrier scattering in ultranarrow-gap semiconductors with degenerate carrier statistics. This behavior is explained by the combined effects of enhanced optical phonon emission scattering and an increase in effective mass due to band filling. Experimentally, photoconductivity was measured over wide ranges of excitation and temperature in unintentionally doped n-type short-period InAsSb0.6/InAsSb0.3 strained-layer superlattices (SLS), relevant for long-wavelength infrared optoelectronic devices. The resistive device impedance, weakly dependent on excess carrier concentration, simplifies broadband impedance matching to low-voltage CMOS driver electronics. At 77 K, 10.6 µm laser excitation led to an initial rise in conductivity, with a decrease observed above 10 W/cm2.

  PublisherOA PDFDOI

• Carrier recombination in MBE grown InGa0.2AsSb0.27 and InAsSb0.09 alloys lattice-matched to GaSb for mid-wave infrared device applications

  Applied Physics Letters · 2025-07-28 · 1 citations

  article

  This study presents the molecular beam epitaxy growth of the indium-rich InGa0.2AsSb0.27 alloy with a 0.26 eV bandgap, lattice-matched (LM) to GaSb. A significant finding is the high material metrics, particularly the minority carrier lifetime (0.3 μs) and the background carrier concentration (8 × 1015 cm−3), in which the product reaches half the value of the reference InAsSb0.09 alloy. This indicates the suitability of indium-rich InGaxAsSby alloys LM to GaSb for low-dark-current, high-quantum-efficiency detectors for the entire mid-wave infrared wavelength range.

  PublisherDOI

• Review of virtual substrate technologies for 6.3 Ångström lattice constants

  Journal of Vacuum Science & Technology A Vacuum Surfaces and Films · 2023 · 6 citations

  • Materials science
  • Optoelectronics
  • Condensed matter physics

  Virtual substrates with lattice constants in the range mid-way between InAs and InSb have been developed using molecular beam epitaxy (MBE). The III–V alloys in this range are of particular interest for narrow bandgap device applications, such as infrared detection. In all cases, GaSb was used as the real substrate and the lattice constant was increased using linear, analog grades of GaInSb or AlGaInSb. We determined the resulting threading dislocation density with x-ray topography in InAsSb films grown on top. We describe the importance of defect reduction for determination of basic materials properties, such as fundamental bandgap, give examples of new device structures that are enabled by this technology, and discuss future directions for possible further improvements.

  PublisherOA PDFDOI

• Short-period InAsSb-based strained layer superlattices for high quantum efficiency long-wave infrared detectors

  Applied Physics Letters · 2022 · 7 citations

  • Materials science
  • Optoelectronics
  • Optics

  Infrared detector barrier heterostructures with strained layer superlattice (SLS) absorbers with different periods were compared. The first was a reference using a conventional barrier heterostructure with a low temperature energy gap corresponding to a wavelength of 10 μm in a 2-μm-thick undoped absorber using a 10.9 nm period with InAs/InAsSb0.36 compositions grown directly on a GaSb substrate. The second structure, in contrast, used a significantly shorter 4.3 nm period absorber with InAsSb0.3/InAsSb0.55 compositions, similar energy gap, and absorber thickness, which were grown on a 6.2 Å lattice constant GaIn0.3Sb virtual substrate on GaSb. It was found that in the short period SLS, the vertical hole mobility and minority carrier lifetime in the temperature range of 80–150 K were a factor on 2–3 greater than in the reference structure. The improvement of the vertical hole mobility was attributed to the effect of hole delocalization. The latter results in an increase in the optical absorption coefficient and the quantum efficiency.

  PublisherDOI

• High power density soft x-ray GaAs photodiodes with tailored spectral response

  Semiconductor Science and Technology · 2022-06-28 · 1 citations

  articleOpen access1st author

  Abstract GaAs photodiode arrays have been designed for non-destructive monitoring of x-ray beam position in soft coherent beamline front ends in synchrotron light sources. A shallow p-on-n junction was employed to reduce the device photocurrent density to optimize the operation with beam power densities up to 20 W mm −2 , mainly coming from hard x-rays. With this approach, the photocurrent is primarily defined by the excess carriers generated by low-energy x-ray photons absorbed near the detector surface. The p–n junction structures were grown by molecular beam epitaxy and processed into 64-element linear photodiode arrays. The devices were characterized first in the visible range with a high-power Ar-ion laser and then tested in the soft and hard x-ray regions up to 10 keV at two beamlines of the National Synchrotron Light Source II. The responsivity was measured to be 0.16 A W −1 at 0.7 keV and 0.05 A W −1 at 6 keV in agreement with modeling. At higher x-ray energies the measured responsivity was lower than predicted in the framework of the carrier diffusion model; a possible explanation is discussed.

  PublisherDOI

• Progress Towards Soft X-Ray Beam Position Monitor Development

  JACOW · 2021-01-01 · 1 citations

  articleOpen access

  X-ray beam position monitors (BPMs) are instrumental for storage ring light sources, where they reliably provide positional measurements of high-power beams in hard X-ray beamlines. However, despite a growing need, coming especially from coherent soft X-ray beamlines, non-invasive soft X-ray BPMs have not been demonstrated yet. We are presently working on a funded R proposal to develop a non-invasive soft X-ray BPM with micron-scale resolution for high-power white beams. In our approach, multi-pixel GaAs detector arrays are placed into the beam halo and beam position is inferred from the pixel photocurrent levels. Presently, the first detector array prototypes have been manufactured and are being prepared for low-power beam tests. The mechanical design of a BPM test-stand, which will be installed in the 23-ID canted soft X-ray undulator beamline at NSLS-II, is well under way. In addition, we are developing new algorithms of beam position calculation which take full advantage of extended multi-pixel detector arrays. In this paper we will review our design choices and discuss recent progress.

  PublisherDOI

• GaAs detector array for soft X-ray beam position monitoring in storage ring light sources

  Conference on Lasers and Electro-Optics · 2021-01-01

  articleCorresponding

  We describe a GaAs detector array for soft-Xray photons with energies above 250 eV designed to operate with power density levels of up to 20 W/mm 2 to be used in a novel beam position monitor.

  PublisherDOI

• Novel Metamorphic Heterostructures for Long Wave Infrared Optoelectronics

  2020-01-05

  article1st authorCorresponding
  Publisher

• A comparison of indium arsenide antimonide and mercury cadmium telluride as long wavelength infrared detector materials

  Journal of Applied Physics · 2020 · 7 citations

  • Materials science
  • Optoelectronics
  • Optics

  The basic material parameters that govern the performance of bulk alloys for long wavelength infrared detection have been calculated for indium arsenide antimonide and mercury cadmium telluride. The numbers show that similar performance could be expected from the two materials provided they can be synthesized at similar degrees of perfection. In order to approach parity, the quality of InAsSb must be optimized, which requires careful variations of molecular beam epitaxy (MBE) growth parameters, namely, substrate temperature and flux magnitudes and ratios. Molecular dynamics-based simulations of MBE growth offer a means to optimize these parameters by providing constants for first-principles or empirical growth models or by directly relating the qualities of the simulation-grown crystals to the MBE parameters.

  PublisherDOI

• Development of the III-V Barrier PhotoDetector Heterostructures for Spectral Range Above 10 microns

  2016-02-14

  article

  Abstract : Novel approach to growth of quality narrow gap InAsSb-based materials using metamorphic buffers on GaSb substrates was pursued. The developed GaInSb and AlInSb graded buffers served as a platform for growth of strain-free low-dislocation-density bulk InAsSb layers. The ability to select the lattice constant up to 3 % greater than that of GaSb eliminated the lattice constant design constrain in the realization of III-V narrow gap semiconductors grown pseudomorphically on the available substrates. The buffers were developed for InAsSb alloys with Sb compositions in the range from 20 to 65 %. The bulk InAsSb layers showed the energy gaps as low as 90 meV at 77 K. nBn and nBp barrier heterostructures with bulk InAsSb absorbers showed high quantum efficiency consistent with the fundamental absorption, efficient hole transport and long carrier lifetime of Ga-free materials. Barrier heterostructures with undoped InAsSb absorbers showed no surface current. The fundamental absorber parameters were determined from transient response of barrier heterostructures to pulsed excitation. Feasibility of the extension of the absorption edge of InAsSb-based materials grown on metamorphic buffers to longer wavelengths preserving minority hole transport was demonstrated experimentally using short-period strained layer superlattices obtained by modulation of Sb composition.

  Publisher

Frequent coauthors

• Gregory Belenky

  Stony Brook University

  9 shared

• Kevin Kucharczyk

  Stony Brook University

  7 shared

• Jinghe Liu

  7 shared

• G. Kipshidze

  Stony Brook University

  6 shared

• С. Г. Аникеев

  National Research Tomsk State University

  5 shared

• Stefan P. Svensson

  DEVCOM Army Research Laboratory

  5 shared

• Jingze Zhao

  Stony Brook University

  5 shared

• ND Gu

  State University of New York

  4 shared

Labs

• Electrical and Computer Engineering - Dmitri Donetski LabPI