Phenomenon Of Photon Emission Research Articles

Hot carrier effects in InGaZnO thin-film transistor

Photon emission and the electrical characteristics of a InGaZnO (IGZO) thin-film transistor (TFT) were evaluated to clarify the existence of hot carriers and their effects. The photon emission was observed from the drain edge of the IGZO-TFT and the capacitance–voltage characteristics indicated that a potential barrier was formed at the drain region when the device is driven by high drain voltage of 30 V. Based on these results, the photon emission phenomenon from the IGZO-TFT was induced by hot carriers that should be considered as a significant degradation mode for a high-performance oxide semiconductor device.

Dielectric haloscopes: sensitivity to the axion dark matter velocity

We study the effect of the axion dark matter velocity in the recently proposed dielectric haloscopes, a promising avenue to search for well-motivated high mass (40–400 μeV) axions. We describe non-zero velocity effects for axion-photon mixing in a magnetic field and for the phenomenon of photon emission from interfaces between different dielectric media. As velocity effects are only important when the haloscope is larger than about 20% of the axion de Broglie wavelength, for the planned MADMAX experiment with 80 dielectric disks the velocity dependence can safely be neglected. However, an augmented MADMAX or a second generation experiment would be directionally sensitive to the axion velocity, and thus a sensitive measure of axion astrophysics.

Nonlinear Breit-Wheeler process in the collision of a photon with two plane waves

The nonlinear Breit-Wheeler process of electron-positron pair production off a probe photon colliding with a low-frequency and a high-frequency electromagnetic wave that propagate in the same direction is analyzed. We calculate the pair-production probability and the spectra of the created pair in the nonlinear Breit-Wheeler processes of pair production off a probe photon colliding with two plane waves or one of these two plane waves. The differences of these two cases are discussed. We evidently show, in the two-wave case, the possibility of Breit-Wheeler pair production with simultaneous photon emission into the low-frequency wave and the high multiphoton phenomena: (i) Breit-Wheeler pair production by absorption of the probe photon and a large number of photons from the low-frequency wave, in addition to the absorption of one photon from the high-frequency wave; (ii) Breit-Wheeler pair production by absorption of the probe photon and one photon from the high-frequency wave with simultaneous emission of a large number of photons into the low-frequency wave. The phenomenon of photon emission into the wave cannot happen in the one-wave case. Compared with the one-wave case, the contributions from high multiphoton processes are largely enhanced in the two-wave case. The results presented in this article show a possible way to access the observations of the phenomenon of photon emission into the wave and high multiphoton phenomenon in Breit-Wheeler pair production even with the laser-beam intensity of order ${10}^{18}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$.

Photon generation by injection of electrons via quantum Hall edge channels

Photon emission caused by quantum electron transport has been found in the quantum Hall effect regime through photon-counting THz microscopy. The imaging reveals that Landau-level emission occurs at the confluence of unequally occupied edge channels in the quantum Hall effect plateau (filling factor $\ensuremath{\nu}=4$) when a potential barrier across the Hall bar is introduced. It is also found that the confluence at the lower-potential sample boundary (with positive Hall voltage) emits more photons than that at the higher-potential one. Since electrons and holes are injected via phase-coherent conducting channels, this photon emission phenomenon will provide a new platform for studying the interplay between quantum electron transport and quantum optics.

Mass gain and loss of non-relativistic electrons in photon-electron interactions

It is shown that the electrons gain mass as their non-relativistic velocities increase. This process is realized by the absorption of photons in the colliding process. In an inverse manner, they loss their mass when they radiate photons. The related equations are derived by using the relativistic mass equation and independently by considering the non-relativistic energy relation. The Compton scattering and photon emission phenomena are revisited with the new theory.

The plasma generated and photons emitted in an oil-lubricated sliding contact

Intensive work has long been going on to find out the unknown origin that sets off curious tribo-physicochemical phenomena and that causes various kinds of problems in oil-lubricated sliding contacts in mechanical and processing systems. The strange tribochemical reaction is one of the such curious chemical phenomena observed in the degradation of perfluoropolyether (PFPE) lubricating oil film in a hard disk drive. Plasma (triboplasma) (Nakayama and Mirza 2006 Tribol. Trans. 49 17) would be one of the most probable origins of the problems if it were generated sufficiently intensely in oil-lubricated sliding contacts, as it is in such a highly energetic state. The generation of plasma was predicted in both dry and oil-lubricated sliding (Nakayama 1997 Japan. J. Tribol. 42 1077, Nakayama 2004 Surf. Coat. Technol. 188–189 599). However, plasma generation in industrially important oil-lubricated contacts has not yet been proven, though it has been found in dry sliding (Nakayama and Nevshupa 2002 J. Phys. D: Appl. Phys. 35 L53). Here the author reports the discovery of the predicted plasma generated in the rear part of an oil-lubricated sliding contact, together with a new finding on photon emission phenomena from inside and outside of the sliding contact in the tribosystem of a diamond pin sliding against a sapphire disc. The plasma in oil-lubricated sliding has a simple ellipse shape, while that in dry sliding has a horseshoe pattern. Visible and infrared (IR) photons are emitted from oil-lubricated sliding contact, while ultraviolet (UV), visible and IR photons are emitted from the region of plasma generation as well as from dry sliding. The UV photon spectra emitted under oil-lubrication completely coincided with those in dry sliding and air discharge, demonstrating that plasma is generated by air discharge even under oil-lubrication. Two kinds of new concepts have been proposed. One is plasma generation by discharge of air through bubble formation in decompressed oil in the rear part of the sliding contact. The other is photon emission from surface atoms and oil molecules excited by the attack of electrons accelerated in the intense tribocharge-induced electric field of the asperity gap inside the sliding contact under dry and oil-lubricated slidings. The size and intensity of the plasma and photon emission from the sliding contact under oil-lubrication increases greatly with the applied normal force and the sliding velocity.

Single molecule of a π-conjugated polymer slowly twinkles in solution at room temperature

A phenylacetylene monomer, 4-(decyloxycarbonyl)phenylacetylene (DecCPA), was synthesized and polymerized using the combined catalyst system, i.e. [Rh(norbornadiene)Cl]2 and triethylamine, to give a yellow solid π-conjugated polymer [poly(DecCPA)] of high molecular weight and cis-transoidal stereo-regular main chain. Poly(DecCPA) was measured using the total internal reflection fluorescence microscopy, which is a single molecule detection technique that is carried out in a tetrahydrofuran solution at room temperature with the light-twinkling of a single molecule being observed. This twinkling is a dynamic photon emission phenomenon of single poly(DecCPA) molecule that we mention specifically as a resultant from the time scale — changing very slowly in the time scale of milliseconds and seconds — with the changed fluorescent intensity being associated with the changing single polymer molecule conformation caused by the micro-Brownian motion. Although molecular dynamics was of the picosecond time scale, generally, this poly(DecCPA) molecule had the mode of the molecular motion of π-conjugated main chain. This was very slow in the second time scale as was shown.

Photon statistics and correlation analysis of ultraweak light originating from living organisms for extraction of biological information

Ultraweak photon emission phenomena in the visible to near-IR region, originating from biological organisms, are known. This biophoton emission is generated during metabolic processes and constitutes physiological information. We investigated a technique for characterizing the optical radiation field based on photon statistics and correlation analysis to extract information on regulation processes in biochemical reactions and their interactions. We developed the system based on the time-interval measurement of photoelectrons in a photon-counting region and employed data processing with a nonstationary optical field with correction for the correlative properties of the photomultiplier dark current. We analyzed biophoton emission from cellular slime mold (Dictyosterium discoideum) and observed the characteristic variation of this organism's super-Poisson statistics during the developmental process.

Photon emission and related hot-carrier effects in polycrystalline silicon thin-film transistors

The photon emission induced by the drain avalanche in polycrystalline silicon thin-film transistors (polysilicon TFTs) has been studied in wide drain and gate voltage ranges. As the photon emission phenomenon is closely related to hot-carrier effects, the gate and drain bias conditions for maximum device degradation have been determined from measurements of the emitted light intensity. In n-channel polysilicon TFTs, the effects of bias stressing at the maximum light emission are related to hot-hole trapping into the gate oxide near the drain and to formation of acceptor-like interface states consisted of midgap states and band tails.

Photon emission in deep submicron Si n -MOSFET

The photon emission phenomenon has been studied in deep submicron MOSFETs (down to 0.1 µm) in a wide drain and substrate voltage range. The authors show that the number of emitted photon is still large for low voltage operation. Moreover, using the influence of a substrate bias, it is shown that the photon emission phenomenon is unambiguously associated with the substrate current and cannot be correlated to the gate current.

生体試料より放出されるBio-Photonの二次元的検出

Ultraweak photon emission phenomena from various living organisms, tissues and cells are recently being recognized and are attracting a great deal of interest. We are currently investigating a highly sensitive ultraweak photon imaging measurement and analysis system based on PIAS and VIMS (Hamamatsu Photonics) for this purpose. We have successfully observed for the first time ultraweak photon counting images of soybean seeds and the root tissues after 1 to 5 days of germination. All images were obtained in complete darkness at room temperature. It is believed that the ultraweak photon emission patterns thus observed is not due to external or artificial stimulation (e. g. fluorescence) but, rather, to intrinsic processes and functions closely related to cell division and growth.

Quantitative Spectrochemical Analyses of Feldspars by Ion Bombardment

WHEN the surface of a solid target is bombarded with energetic ions or neutral atoms, spontaneous emission of ultraviolet and visible radiation is observed. When the radiation is analysed by a spectrometer, it is shown to contain characteristic lines of the constituent elements in the solid1–4. It has also been shown that this radiation is caused by the decay of excited atoms ejected from the target surface4,5. The photon emission process is more efficient in insulating targets than metallic targets. This is because of the existence of radiationless de-excitation processes which compete with radioactive decay in the case of metals but not in the case of insulators1,6. The intensities of the spectral lines are directly proportional to the bombarding ion beam current7, that is, directly proportional to the number of sputtered particles since the sputtering yield (sputtered atoms per incident ion) for a particular material is invariant if the ion energy is constant providing that the surface conditions do not alter during sputtering. In a previous report1, one of us suggested that the photon emission phenomenon may provide a new method for chemical analysis of solids, and subsequently White et al.3 demonstrated the detection sensitivity, for example 1 part per 106 for sodium in a silicate glass, which could be achieved with this technique. This communication describes some quantitative analyses of a number of feldspars. The analyses were made by comparing the intensities of the emission lines of the major constituents in these materials. In our analyses, we assume that diffusion does not occur to an appreciable extent so that the relative sputtering rates are directly proportional to the atomic concentrations in the target. Provided that self-absorption is negligible (because the ‘vapour’ density of absorbing atoms is low), then we have the condition for spectrochemical analyses (intensity is directly proportional to concentration).