Mesaelements of the focal plane array (FPA) of
p
–
i
–
n
diodes based on Al
x
Ga
1–
x
N for
p–i–n
heteroepitaxial structures (HESs) grown by the molecular-beam epitaxy and hydride epitaxy methods ...with the use of metalorganic compounds are formed. Elements of 320 × 256 FPAs with a pitch of 30 μm are separated by means of ion-beam etching through a photoresist mask in the argon ion stream produced by the Kaufmann ion source in a vacuum plant. To determine the required etching depth, contact profilometry and ultraviolet spectrophotometry methods allowing one to determine positions of the
n
-layer and sufficient etching depth of the sample are used. The thickness accuracy of the HES functional layers stated in manufacturer’s certificates does not exceed 28%. Rates of ion-beam etching of Al
x
Ga
1–
x
N for
p–i–n
layers with different compositions are determined.
Features of the electrical properties of
n
(
p
)-Hg
1–
x
Cd
x
Te (
x
= 0.21–0.23) with Al
2
O
3
or SiO
2
/Si
3
N
4
dielectrics are considered. The HgCdTe films were grown by means of molecular beam ...epitaxy on GaAs(013) and Si(013) substrates. The possibility of determining the basic parameters of MIS structures based on
n
(
p
)-Hg
1–
x
Cd
x
Te (
x
= 0.21–0.23) with and without a varizonal layer from admittance measurements in a wide range of temperatures and frequencies is discussed.
In this paper it is highlighted and argued that Boscovich’s natural sciences theory is so deeply rooted in metaphysics and pervaded by it, we can maintain that it is a distinctive example of ...sharp-witted, clever and far-reaching metaphysical natural philosophy. Critically engaging with the unsubstantiated denial of metaphysics and several centuries-long attempts to overcome it, I demonstrate that by metaphysical thinking Boscovich arrived at his unique notion of attractive-repulsive force and gained insight into the structure of things, by which he anticipated, among other things, the theory of relativity and quantum physics. Although Boscovich greatly and successfully used quantitative methods while solving problems from geodesy, astronomy, optics, civil engineering statistics, hydraulic engineering and other fields – the most important parts of his natural sciences legacy, which made him transpose several centuries, are supported by geometric intuition and carried out mainly by qualitative methods, that is, metaphysical speculation. Also, I explain how for the creation and development of electromagnetism it was crucial to describe electromagnetic phenomena using Boscovich’s unique law of force and his theory of the structure of matter, what was explicitly stated by the ‘father of electromagnetism’ James Clerk Maxwell. Boscovich would have never reached these ideas by the exact scientific method, only by metaphysically founded and guided ‘proper thinking’.
A double heterostructure based on direct-gap semiconductors with a photoabsorption middle layer at the avalanche breakdown voltage is considered. Such structures are used in the development of ...avalanche photodiodes with separate absorption and multiplication regions (APD with SAMR). It is shown that impact generation of electron–hole pairs should be considered in calculating the maximum possible characteristics of APDs with SAMR even in the absorption layer; therewith, this can be performed analytically.
Posljednji đerski i prvi pečuški tezarij Josipa Franje Domina, sastavljeni od 25 teza »iz eksperimentalne fizike«, a naslovljeni De corpore generatim, bili su prvi tezariji što ih je Zagrepčanin ...tiskao nakon što je objavio raspravu Dissertatio physica de aeris factitii genesi, natura, et utilitatibus (1784.), a izlažu jezgru prirodne filozofije u obliku nauka o ustroju tvari, temeljnim silama u prirodi i općim svojstvima tijelā, zatim mehaniku i nauk o gravitaciji te osnove kemije i astronomije. Tiskani u travnju 1785. i 1786. godine, oni označuju prijelomnicu u Dominovim prirodnofilozofskim gledištima. U đerskom tezariju 1785. Domin prvi put poimence spominje Boškovića i prvi put zadaje tezu o kemiji kao znanosti. Prvi spomen Boškovićeva prezimena podudara se s Dominovom transformacijom iz strogoga boškovićevca, kakav je bio u tezarijima od 1778. do 1784. godine, u prirodnoga fillozofa koji se nastoji izboriti za vlastite uvide. Teza o kemiji kao »znanosti podređenoj eksperimentalnoj fizici« svjedoči pak o utjecaju Dominova kompendija o kemiji plinova, ali je i programatski korak naprijed: »najjednostavnija počela« tijela Zagrepčanin naziva molekulama. U pečuškom tezariju 1786. Domin prvi put dodaje tezu o sili inercije, kamenu kušcu tadašnjih prirodnofilozofskih rasprava. Stoga oznaka »iz eksperimentalne fizike« s naslovnice tezarija ne znači da Domin isključuje prirodnu filozofiju iz svojih razmatranja, štoviše, ne znači da Domin prestaje biti filozofom prirode. Upravo obratno, kao »profesor teorijske i eksperimentalne fizike te mehanike kao i poljoprivrede« Domin se suočava s cijelim prirodnofilozofskim nasljeđem epohe, a glavni su mu sugovornici Newton, Bošković i dva boškovićevca: Leopold Biwald u Grazu i Ivan Krstitelj Horvath u Trnavi, Budimu i Pešti. Svoje stavove Domin ponekad oblikuje prema Boškovićevu tumačenju, ponekad s izričitim odmakom od Boškovića, a ponekad se vraća izvornom Newtonu.
Two exam thesauri De corpore universim by Josip Franjo Domin, composed of 25 theses in the field of “experimental physics”, the last published in Györ in 1785 and the first published in Pecs in 1786, saw light soon after the printing of his treatise Dissertatio physica de aeris factitii genesi, natura, et utilitatibus (1784), and expounded the core of natural philosophy in the form of a doctrine of the structure of matter, fundamental forces in nature, and general properties of physical bodies, then mechanics and doctrine of gravitation, along with the basis of chemistry and astronomy. Being published in April 1785 and April 1786, they represent a turningpoint in Domin’s views in natural philosophy. In the 1785 thesaurus, Domin for the first time mentions Bošković by name, and also for the first time proposes a thesis on chemistry as science. The first mention of Bošković’s surname corresponds with Domin’s transformation from a strict Boscovichian, as confirmed in the the sauri from 1778 to 1784, into a natural philosopher who comes forth with his own insights. The thesis on chemistry as “a science subordinated to experimental physics” is the fruit of Domin’s compendium on the chemistry of gases, yet, at the same time, is a programmatic step forward: Domin refers to “the simplest principles” of the bodies as molecules. In the 1786 thesaurus Domin introduces the thesis on inertia, touchstone of the then discussions in the field of natural philosophy. Therefore, “experimental physics” suggested in the thesauri title does not imply that Domin excluded natural philosophy from his considerations. Quite the reverse: as a “professor of theoretical and experimental physics, mechanics, and agriculture”, Domin is challenged by the legacy of the natural philosophy of the epoch, notably by Newton, Bošković and two Boscovichians – Leopold Biwald in Graz and Ivan Krstitelj Horvath in Tyrnau, Buda and Pest. Thus Domin either tends to mould his views in accordance with Bošković’s natural philosophy, or departs from Bošković or Boscovichians significantly, or shifts towards the natural philosophy of Newton.
The (multiple) photoionization and subsequent fragmentation of the C60 molecule was studied with the synchrotron radiation after removing electrons from the inner K-shell. Our intention was ...especially focused on the dynamics of the subsequent fragmentation. In addition to ’normal’ (non-coincident) electron and ion time-of-flight spectroscopy, we investigated this topic with the help of an electron–electron-coincidence measurement. Our experiment shows that in these processes Cq+ 60 ions with charge states up to 3+ and several smaller Cq+ 60-2m fragments are formed. In addition, the broad peak besides the C(1s) line, usually referred to as the 'plasmon' peak, has been observed. / (Многогранная) фотоионизация и сопроводительная фрагментация молекулы C60 исследовалась с помощью синхротронного излучения после выброса электрона из внутренней К-оболочки. Наше исследование было сосредоточено на динамике сопроводительной фрагментации. Кроме «нормальной» (несовпадающей) электронной и ионной спектроскопии, применялись и другие методы измерений, так например, было проведено измерение электронного совпадения. Наш эксперимент показал, что в течение этих процессов формируются Cq+ 60 ионы с зарядом до трех + и несколько небольших Cq+ 60-2m фрагментов. Кроме того, был выявлен широкий пик рядом с основной линией C (1s), так называемым «плазмоном». / Fotojonizacija (višestruka) i prateća fragmentacija molekula C60 proučavana je uz pomoć sinhrotronskog zračenja nakon izbacivanja elektrona iz unutrašnje K-ljuske. Naše istraživanje bilo je posebno fokusirano na dinamiku prateće fragmentacije. Pored 'normalne' (nekoincidentne) elektronske i jonske TOF spektroskopije, ovu temu izučavali smo i uz pomoć elektron-elektron koincidentnog merenja. Naš eksperiment pokazuje da se u ovim procesima formiraju Cq+60 joni sa naelektrisanjem do 3+ i nekoliko manjih Cq+60-2m fragmenata. Pored toga, pored glavne C(1s) linije uočen je široki pik, tzv. plazmon.
A photodetector array chip for detection of the optical signal in a wave range of 0.4–1.0 μm; conversion of the optical signal into the electric signal; and its extraction in the analog form to 1, 2, ...4, 8, or 16 outputs has been designed, fabricated, and studied. The main parameters of this chip are the following: the charge capacity is up to 200000 electrons, the frame rate is higher than 600 Hz at the maximum resolution, and the integrated sensitivity is up to 1000 V/(lx s).
The influence of indirect transitions of Г-L and Г-Х types in the Brillouin zone on optical and electrophysical characteristics of heteroepitaxial layers of А
3
В
5
compounds is estimated by the ...example of ternary (InGaAs) and quaternary (InGaAsP) compounds. It has been found that consideration of indirect transitions lowers the refractive index of semiconductor compounds by up to 15% in a narrow wavelength range of 0.4—0.6 μm.
The long-term stability of a 640x512 InSb focal plane array (FPA) with a pitch of 15 μm combined with a Stirling cooler and an interface block has been investigated.The dependences of the FPA ...correctability index on the operation time after a two-point correction of the irregularity have been obtained. The FPAs with two different circuits of the readout LSI cells that differ in the integration capacitance and transmission coefficients are considered. It has been found that, for the InSb FPA, the long-term stability is as high as several hours, which ensures continuous operation of the array in thermal imaging systems without additional calibrations.
The characteristics of focal plane arrays (FPAs) based on (quantum-well infrared photodetector) QWIP structures with 384 × 288 elements spaced at the intervals 25 μm are investigated. The difference ...in spectral and current–voltage characteristics is established for epitaxial QWIP wafers. The output signal is found to vary over the area of photosensitive elements with gradients in different directions. The photoelectric FPA parameters depend strongly on the temperature of the cooled assembly and the bias at the photosensitive element. The noise-equivalent temperature difference is 30 mK at the frame rate 120 Hz and the cooled assembly temperature 65 K.