Heat capacity of bulk boron doped single crystal HPHT diamonds in the temperature range from 2 to 400 K

Heat capacity Ср of boron-doped single crystal diamonds grown by the temperature gradient method was studied. Boron content was about < 10¹⁶, ~ 10¹⁸ and ~ 10²⁰ cm⁻³. Heat capacity data for all tested crystals match well within the measurement accuracy (1 %) in the temperature range of 150–400 K and obey the Debye law. At low temperatures heat capacity follows linear law possibly due to metallic inclusions in diamond bulk. Using this data the amount of metal can be calculated for each sample.Досліджено теплоємність Ср легованих бором монокристалічних алмазів, вирощених методом температурного градієнта. Вміст бору був < 10¹⁶, ~ 10¹⁸ і ~ 10²⁰ см⁻³. Дані по теплоємності для всіх досліджених кристалів добре узгоджуються в межах точності вимірювань (1 %) в інтервалі температур 150–400 К і підпорядковуються закону Дебая. При низьких температурах теплоємність змінюється за лінійним законом, можливо, через наявність металевих включень в алмазі. Використовуючи ці дані, кількість металу може бути обчислена для кожного зразка.Исследована теплоемкость Ср легированных бором монокристаллических алмазов, выращенных методом температурного градиента. Содержание бора было < 10¹⁶, ~ 10¹⁸ и ~ 10²⁰ см⁻³. Данные по теплоемкости для всех исследованных кристаллов хорошо согласуются в пределах точности измерений (1 %) в интервале температур 150–400 К и подчиняются закону Дебая. При низких температурах теплоемкость изменяется по линейному закону, возможно, из-за присутствия металлических включений в алмазе. Полученные данные позволяют рассчитать долю металлических включений в каждом из образцов

Temperature effects on an InGaP (GaInP) (55)Fe X-ray photovoltaic cell.

This paper investigates the effects of temperature on an InGaP (GaInP) (55)Fe X-ray photovoltaic cell prototype for a radioisotope microbattery (also called a nuclear microbattery). An In0.5Ga0.5P p-i-n (5 μm i-layer) mesa photodiode was illuminated by a standard 206 MBq (55)Fe radioisotope X-ray source and characterised over the temperature range -20 °C to 100 °C. The electrical power output of the device reached its maximum value of 1.5 pW at a temperature of -20 °C. An open circuit voltage and a short circuit current of 0.82 V and 2.5 pA, respectively, were obtained at -20 °C. While the electrical power output and the open circuit voltage decreased with increasing temperature, an almost flat trend was found for the short circuit current. The cell conversion efficiency decreased from 2.1% at -20 °C to 0.7% at 100 °C

Excitation of hypersonic acoustic waves in diamond-based piezoelectric layered structure on the microwave frequencies up to 20 GHz

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.First ultrahigh frequency (UHF) investigation of quality factor Q for the piezoelectric layered structure «Al/(001)AlN/Mo/(100) diamond» has been executed in a broad frequency band from 1 up to 20 GHz. The record-breaking Q f quality parameter up to 2.7 1014 Hz has been obtained close to 20 GHz. Frequency dependence of the form factor m correlated with quality factor has been analyzed by means of computer simulation, and non-monotonic frequency dependence can be explained by proper features of thin-film piezoelectric transducer (TFPT). Excluding the minimal Q magnitudes measured at the frequency points associated with minimal TFPT effectiveness, one can prove a rule of Qf f observed for diamond on the frequencies above 1 GHz and defined by Landau-Rumer’s acoustic attenuation mechanism. Synthetic IIa-type diamond single crystal as a substrate material for High-overtone Bulk Acoustic Resonator (HBAR) possesses some excellent acoustic properties in a wide microwave band and can be successfully applied for design of acoustoelectronic devices, especially the ones operating at a far UHF band

Excitation of hypersonic acoustic waves in diamond-based piezoelectric layered structure on the microwave frequencies up to 20 GHz

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.First ultrahigh frequency (UHF) investigation of quality factor Q for the piezoelectric layered structure «Al/(001)AlN/Mo/(100) diamond» has been executed in a broad frequency band from 1 up to 20 GHz. The record-breaking Q f quality parameter up to 2.7 1014 Hz has been obtained close to 20 GHz. Frequency dependence of the form factor m correlated with quality factor has been analyzed by means of computer simulation, and non-monotonic frequency dependence can be explained by proper features of thin-film piezoelectric transducer (TFPT). Excluding the minimal Q magnitudes measured at the frequency points associated with minimal TFPT effectiveness, one can prove a rule of Qf f observed for diamond on the frequencies above 1 GHz and defined by Landau-Rumer’s acoustic attenuation mechanism. Synthetic IIa-type diamond single crystal as a substrate material for High-overtone Bulk Acoustic Resonator (HBAR) possesses some excellent acoustic properties in a wide microwave band and can be successfully applied for design of acoustoelectronic devices, especially the ones operating at a far UHF band

Intracenter dipole transitions of a hydrogen-like boron acceptor in diamond: oscillator srengths and line broadening

Substitutional boron in diamond acts as an acceptor center with the ionization energy of about 372 meV. Unlike its analogues in elemental semiconductors (silicon, germanium), boron bound states are poorly described by the electronic mass approximation due to the large ionization energy and the small spin-orbit splitting of the valence band in diamond. Thereby experimental investigations appear to be a main way of study of discrete electronic states of boron in diamond. In this paper, we report infrared (IR) absorption spectroscopy results obtained for HPHT-grown single crystal diamonds doped with natural boron (80% 11B – 20% 10B), and with isotopically enriched boron (99% 11B – 1% 10B). A moderate dopant concentration (1e16–1e17 / cm3), low concentration of lattice defects and vanishing thermal impact at cryogenic temperatures provided significantly reduced line broadening so that more than 60 boron transitions could be spectrally resolved. Mathematical approximation of the spectral lines revealed the main empiric features of zero-phonon dipole intracenter transitions: their energy, linewidth and integrated absorption. This allowed us to calculate oscillator strength of the boron acceptor transitions in diamond. The Lorentzian shape of the spectral lines indicates dominating uniform broadening of the transitions. Together with the relatively broad linewidths (0.1–0.5 meV) it reveals strong electron-phonon interaction in boron-doped diamond

Low temperature thermal conductivity of heavily boron-doped synthetic diamond: Influence of boron-related structure defects

Thermal conductivity of single-crystal boron-doped diamonds (BDD) with ~ 2∙10¹⁹ cm⁻³ (~ 120 ppm) and 5∙10¹⁹ cm⁻³ (~ 300 ppm) boron content was studied by a steady-state method in a temperature range of 20–400. K. The obtained data were analyzed within Callaway model framework. The values of dislocation density obtained from best fit of experimental data and from density of etch pits measuring were compared. Their discrepancy suggests presence of some other boron-related defects in crystal lattice.Теплопровідність монокристала, легованого бору (BDD) із вмістом бору ~ 2∙10¹⁹ cм⁻³ (~ 120 ppm) та 5∙10¹⁹ cм⁻³ (~ 300 ppm), було вивчено прийнятим методом в температурному діапазоні 20–400 К. Результати було проаналізовано в рамках моделі Каллавэй. Отримані значення щільності дислокацій добре узгоджуються з експериментальними даними і збігаються зі щільністю яскравих ямок травлення. Їх відмінність передбачає наявність деяких інших пов’язаних з бором дефектів в кристалічній решітці.Теплопроводность монокристалла, легированного бором (BDD) с содержанием бора ~ 2∙10¹⁹ cм⁻³ (~ 120 ppm) и 5∙10¹⁹ cм⁻³ (~ 300 ppm), была изучена принятым методом в температурном диапазоне 20–400 К. Полученные данные были проанализированы в рамках модели Каллавэй. Полученные значения плотности дислокаций хорошо согласовывались с экспериментальными данными и сравнивались с плотностью ямок травления. Их различие предполагает присутствие некоторых других связанных с бором дефектов в кристаллической решетке