Article
Physics, Applied
Rigo A. Carrasco, Christian P. Morath, Julie V. Logan, Kevin B. Woller, Perry C. Grant, Haylie Orozco, Marko S. Milosavljevic, Shane R. Johnson, Ganesh Balakrishnan, Preston T. Webster
Summary: In this study, quinary GaInAsSbBi alloy was successfully grown by molecular beam epitaxy, and its optoelectronic properties were characterized. The experimental results show that the alloy has a small bandgap energy and a long minority carrier lifetime, indicating its potential for applications in infrared optoelectronic devices.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Philip C. Klipstein
Summary: In a photodiode made from a narrow bandgap III-V material such as InSb, the dominant dark current mechanism is thermal generation-recombination in the depletion region. XBn or XBp barrier detectors suppress the generation-recombination current by using a wide bandgap barrier material. Diffusion limited barrier detectors have a unity gain device architecture that is fundamentally different from traditional photodiodes. High performance barrier detector arrays for mid- and long-wave infrared detection have been developed using bulk alloy and type II superlattice (T2SL) absorbers.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Yan Zhu, Thorsten Trupke, Ziv Hameiri
Summary: This study introduces a dynamic calibration method for injection-dependent carrier lifetime measurements, which compares lifetime measurements under quasi-steady-state and non-quasi-steady-state conditions to achieve precise calibration of experimental data and provide the net bulk doping concentration.
Article
Physics, Applied
A. T. Newell, J. V. Logan, R. A. Carrasco, Z. M. Alsaad, C. P. Hains, J. M. Duran, G. Ariyawansa, G. Balakrishnan, D. Maestas, C. P. Morath, S. D. Hawkins, A. Hendrickson, P. T. Webster
Summary: The effect of majority carrier concentration and minority carrier lifetime on the performance of mid-wave infrared nBn detectors with variably doped InGaAs/InAsSb type-II superlattice absorbers is investigated. The doped detectors show lower dark current densities compared to the undoped counterpart due to the reduction in diffusion current and suppression of depletion current. The device with graded doping exhibits the highest sensitivity with a shot noise-limited noise-equivalent irradiance, providing insight into the material and device design factors that must be considered to realize a device with optimal sensitivity.
APPLIED PHYSICS LETTERS
(2023)
Article
Energy & Fuels
Bernd Steinhauser, Tim Niewelt, Armin Richter, Rebekka Eberle, Martin C. Schubert
Summary: Recent advancements in surface passivation technology and wafer pretreatment have significantly improved the achievable minority charge carrier lifetime in crystalline silicon. The main limitation identified in this study is likely caused by silicon bulk recombination, possibly due to impurities. Despite these limitations, the measured lifetimes on p-type and n-type crystalline silicon wafers exceed previously reported values.
Article
Energy & Fuels
Alexandra M. M. Bothwell, Carey L. L. Reich, Adam H. H. Danielson, Arthur Onno, Zachary C. C. Holman, Walajabad S. S. Sampath, Darius Kuciauskas
Summary: The efficiencies of thin-film photovoltaic devices are limited by carrier recombination. It is crucial to understand recombination mechanisms to enhance performance. Determining the bulk minority carrier lifetime (tau(bulk)) is challenging in P-N junction devices, especially in highly doped ones. This research utilizes time-resolved photoluminescence simulations to quantify recombination properties and develop methods for determining tau(bulk) in highly doped CdSeTe structures.
Article
Chemistry, Multidisciplinary
Olivera Vukovic, Giulia Folpini, E. Laine Wong, Luca Leoncino, Giancarlo Terraneo, Munirah D. Albaqami, Annamaria Petrozza, Daniele Cortecchia
Summary: This study investigates the size-dependent optoelectronic properties of CsPbI3 nanocrystals through temperature and pressure modulation. It is found that larger particles exhibit increased non-radiative losses and weaker exciton-phonon coupling, leading to decreased luminescence efficiency. Furthermore, a solid-solid phase transition from the gamma-phase to the delta-phase is observed in the nanocrystals, with the optical response strongly dependent on the size of the nanocrystals.
Article
Engineering, Electrical & Electronic
Ernest Rogowicz, Jan Kopaczek, Joanna Kutrowska-Girzycka, Maksym Myronov, Robert Kudrawiec, Marcin Syperek
Summary: Si-based mid-infrared photonics is an emerging technology where Ge1-xSnx alloys can play a fundamental role in Si-compatible photonic components. The research results significantly expand the understanding of carrier relaxation dynamics in Ge1-xSnx epitaxial material, revealing the critical role of band gap inhomogeneity and below-band gap states in the light generation process.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Optics
Sida Wei, Xiaodong Gao, Xiaodan Wang, Yangye Pan, Xionghui Zeng, Jiafan Chen, Shunan Zheng, Ke Xu
Summary: Time-resolved photoluminescence measurements were used to study the minority carrier recombination mechanism of p-GaN films grown on different GaN substrates. The slow decay lifetime of the m-plane Mg-doped GaN reached a record value of 493.7 ps. The decrease in non-radiative recombination centers resulted in a longer slow decay lifetime for the m-plane sample.
JOURNAL OF LUMINESCENCE
(2023)
Article
Construction & Building Technology
Wallace W. L. Lai, Ray K. W. Chang, Christoph Volker, Bella W. Y. Cheung
Summary: This study investigates the dispersion of GPR wave's phase velocity at different wideband frequencies in plywood and concrete, finding greater dispersion in low frequency regimes. The methodology includes time-frequency analysis and coherence plotting to determine the effective frequency bandwidths.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Energy & Fuels
Joerg Horzel, Sebastian Mack, Ioan Voicu Vulcanean, Karin Zimmermann, Sebastian Pingel, Wolfram Kwapil, Felix Maischner, Hannes Hoeffler, Sattar Bashardoust, Dirk Wagenmann, Johannes Greulich, Johannes Seif, Anamaria Steinmetz, Jochen Rentsch
Summary: Industrial mass production of solar cells is shifting towards carrier-selective junction solar cells with passivating contacts. The use of Ga-doped p-type Cz-Si material is still a viable option and offers the advantage of lower wafer costs.
Article
Chemistry, Multidisciplinary
Lisa Kruckemeier, Zhifa Liu, Thomas Kirchartz, Uwe Rau
Summary: The extraction of photogenerated charge carriers and the generation of a photovoltage are crucial in solar cells. In this study, a new method was developed to analyze transient photovoltage measurements by comparing rise and decay times of photovoltage. Through this analysis, the rates of carrier recombination and extraction as a function of bias voltage were determined, providing insights into efficiency losses in perovskite solar cells.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
J. A. Peters, Z. Liu, O. Bulgin, Y. He, V. V. Klepov, M. C. De Siena, M. G. Kanatzidis, B. W. Wessels
Summary: Excitons in Bridgman grown halide perovskite CsPbBr3 single crystals were studied using photoluminescence (PL) spectroscopy to determine their electronic states, revealing strong temperature-dependent photoluminescence intensity and multiple strong bands at the band edge attributed to free or trapped excitons with strong electron-phonon coupling. The average phonon energy and Huang-Rhys parameter indicated a significant electron-phonon interaction, leading to the formation of small polarons and trapped excitons. Transient photoluminescence responses indicated a multiphonon recombination process, with average lifetimes of 17 ns for free excitons and 38 ns for trapped excitons. Native defects and phase transitions were identified as potential causes for the observed edge states, suggesting that eliminating trapping sites could improve charge transport and detector properties.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Lisa Kruckemeier, Zhifa Liu, Benedikt Krogmeier, Uwe Rau, Thomas Kirchartz
Summary: Transient photoluminescence (TPL) and transient photovoltage (TPV) measurements were studied in the field of halide-perovskite photovoltaics. The experiment showed that effective monomolecular lifetimes of around 2 μs can be consistently measured in efficient methylammonium lead-iodide solar cells using both TPL and TPV methods.
ADVANCED ENERGY MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Chunlai Huang, Peng Wu, Lei Wang, Deren Yang
Summary: The study found that the formation of the red zone in casting silicon ingots is not only related to metal impurities, but also to the relatively high concentration of interstitial oxygen.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2021)