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The performance of a NaI(Tl) crystal coupled to a Large Area Avalanche Photodiode (LAAPD) was investigated as a function of temperature in the range from -40[degrees]C to +23[degrees]C. The number of electron-hole pairs created per 1 MeV of [gamma]-ray energy detected by the scintillator, non-proportionality and the energy resolution for various peaking times were measured. It showed a significant variation of the light output and the energy resolution of a NaI(Tl) crystal at reduced temperatures down to -40[degrees]C, as measured with different peaking times in the spectroscopy amplifiers. A large slowing down of the light pulse, caused by the intense slow component of the light pulse, requires long peaking times (up to 48 [micro]s) in order to optimize the energy resolution at the most reduced temperatures. In these conditions of a full integration of the light, a weak variation of the light output of a NaI(Tl) crystal is observed, corresponding to -0.16%/[degrees]C. The non-proportionality characteristics and intrinsic resolution are somewhat distorted by a partial integration of the light by too short shaping in the amplifier. It confirms the earlier observations that, for crystals which exhibited two component decays of the light pulse, the best non-proportionality and the lowest intrinsic resolution are achieved for the full integration of the light. Index Terms--Intrinsic energy resolution, large area avalanche photodiode, NaI(Tl), non-proportionality of light output, temperature dependence.

The steady state Shockley-Read-Hall kinetics are used to study the effects of energy distributions of Si/Si[O.sub.2] interface traps in the energy gap oxidized silicon on the current versus voltage line shape of the electron-hole recombination current. It is concluded that the electron-hole traps at the Si/Si[O.sub.2] interface are more likely to have a U-shaped DOS than discrete few-level interface traps around the Si midgap.

A comprehensive study of emitter-ledge thickness of InGaP/GaAs heterojunction bipolar transistors (HBTs) is conducted. Results reveal that the recombination rate and electron densities are drastically increased near the exposed base surface between the base contact and the emitter ledge.

An investigation is conducted on the modulation mechanisms in photoreflectance (PR) spectroscopy of an ensemble of self-assembled semiconductor quantum dots (QDs). Results reveal that the modulation of QD transitions related to a possible modification of the dot properties due to filling them with carriers is negligible in PR experiment on an ensemble of dots.

A comprehensive quantum anisotropic transport model for holes is used to study silicon PMOS inversion layer transport under arbitrary stress. The results have shown that the hole band structure is dominated by 12 'wings,' where mechanical stress, as well as the vertical field under certain stress conditions, alter the energies of the few lowest hole subbands, changing the transport effective mass, density-of-states, and scattering rates, and thus affecting the mobility.

A study is conducted to show that C-dust-free hole-opening in single-walled carbon nanohorns (SWNHs) and heat-treated single-walled carbon nanotubes (SWNTs) could be easily achieves using slow combustion. The results reveal that the quantity of C-dust was greatly reduced by slow combustion using a low-temperature-increase and a low oxygen concentration.

A numerical study was conducted to investigate the effects of heating the floor of the shallow cavity. A parametric analysis was carried out, where and the influences Cavity aspect ratio. turbulence level of the oncoming flow, and Reynolds number was analyzed.

A kinetic model is presented for assessing the photocatalytic degradation of water-dissolved pollutant species at suspension of TiO2 nanoparticles. The model is based on the sequence of reactions occurring at the semiconductor/electrolyte interface under illumination, and emphasizes the degree of electronic interaction of dissolved pollutant species with the semiconductor surface.

Physical processes responsible for the generation of hole traps in silicon dioxides are investigated. It is indicated that the most important processes for hole-trap generation are found to be in direct interaction of injected holes with the oxide.

The properties of generated and as-grown hole traps in silicon dioxides are studied. Generated hole traps consist of two components, which are cyclic positive charges (CPC) and anti-neutralization positive charges (ANPC).

The structure of metal semiconductors-metal photo detectors (MSMPDs) has been used to investigate the modified and unmodified Schottky barrier heights for holes on GaAs. By using a thin and doped top layer, the barrier height can be varied over a wide range and by using a modified height of 0.79 eV, a reduction has been achieved in the dark current for over three orders of magnitude for MSM photo detectors.

A study of excitation spectra of trans-free base isobacteriochlorin in an n-octane Shpol'skii matrix at liquid helium temperatures is presented. The isobacteriochlorin molecule inhabits two sites (A and B) on rapid cooling.

The laser-induced fluorescence vibronic spectra of single tetracene (C18H12) and pentacene (C24H14) molecules embedded in superliquid 4He(sub N) droplets exhibits a splitting of the zero phonon line (ZPL) into sharp and unequal peaks, accompanied by weaker phonon wings (PW) on the blue side. Hole-burning measurements with two pulsed dye lasers and lifetime measurements suggested that inside He droplets the ground and excited states of tetracene are each split into two levels.

A study is done on spectral holes, which were burned within the inhomogeneous 0,0 fluorescence excitation lines of the T0 -> T1 transition of 2,2-dinaphthylcarbene (2,2-DNC) in n-heptane at 1.7 K. In conclusion, under enforced high symmetry, the number of possible electronic transitions between different spin sublevels of the ground T0 and excited T1 states is reduced and an analysis is shown.

Two-color photon-gated persistent spectral hole burning by electron transfer from a doped donor to an acceptor branched to a host polymer matrix was investigated. The results confirmed that the hole formation mechanism was donor-acceptor electron transfer. Thermal stability of the burnt holes increased when the acceptor was branched into the host polymer, poly(methylmethacrylate).

The off-state instabilities of n-channel metal oxide semiconductor field effect transistors that have undergone thermal nitridation are studied. The latter prompts a barrier height decrease at the Si/SiO2 interface that leads to gate oxide hot-hole injection under conditions of band-to-band tunneling. This yields a higher off-state gatecurrent and a reduction in the gate-induced drain leakage current.

Defects in n-type GaAs layers grown by molecular beam epitaxy due to ion irradation were studied in comparison to damage due to electron irradiation. Results obtained using deep level transient spectroscopy showed that proton irradiated GaAs featured traps similar to those found in electron irradiated materials. Two of the traps were associated with defects which were more complex than simple interstitial-vacancy pairs. However, there were also two traps not present in the electron irradiated GaAs.

The influence of the annealing temperature on the hole density and lattice relaxation of GaAs and AlxGa1-xAs doped with carbon was investigated. The results showed that annealing at temperatures equal to or lower than 550 degrees celsius resulted in increased hole concentration but decreased hole mobility. However, annealing of heavily doped samples at higher temperatures reduced the hole concentration but increased the lattice parameter of the epilayer.

The influence of electron hole scattering on semiconductor current flow was investigated. The results showed that the relative velocities of electrons and holes determined the degree to which electron hole scattering affected the current flow. Electron hole scattering had the greatest effect during conduction in high level injection due to the lack of opposite direction drift velocities in electrons and holes. However, ambipolar diffusion was not affected by electron hole scattering since the carriers moved in the same direction.

The hole mobilities of 1,1-bis(di-4-tolylaminophenyl)cyclohexane doped bisphenol-A-polycarbonate over a range of concentrations were investigated. The results showed that the hole mobilities were heavily dependent on concentration. Increased doping levels resulted in increased dependence. Decreased doping concentration resulted in increased energetic and positional disorder due to dipole moments of the carbonyl groups.

A hole transport equation is obtained to describe the effect of oxide breakup on the base current of n+-polysilicon emitter bipolar devices. Based on a transport model of the emitter's polysilicon/silicon interface, the equation accounts for the observed base current variances as a function of a percentage of the interface void. It also forecasts a lower reliance of the base current on the percentage of interface oxide breakup area for devices satisfying certain conditions.

The neutral divacancies in the Ga-related III-V compound semiconductors were studied using tight-binding calculations of their electronic structure. The calculations were based on the recursion method and supercell approximation. It was shown that each divacancy introduces seven defect levels with three located at the edges of the lower gap and four in the fundamental band gap. It was also shown that the last occupied a1 and e fundamental gap in the neutral divacancy of the three Ga-related III-V compound semiconductors stay at close energies and have different localization characters.

The minority carrier diffusion length and edge surface-recombination velocity in GaAs p/n concentrator solar cells were investigated. The results showed that the hole minority carrier diffusion length tended to increase in regions far from the depletion region. Diffusion length increased sharply as the junction was approached.

An analysis of the time-resolved nonlinear optical transmision measurements in biased quantum-wells shows that the field screening and excitonic saturation mechanisms are clearly identifiable and share similar magnitudes. Results also show that the diffusive conduction phenomena is a significant factor in the process and imply that the main sweep-out mechanism is thermal-based.

Type-2 multiple quantum-wells (MQWs) are analyzed in terms of their optical nonmlinearities. Indirect transition energies are diverted by the space-charge potential resulting from the separation of electrons from holes in the MQWs while direct transitions remain unaffected by the space-charge field. A Coulomb-enhancement peak occurs at the hole quasi-chemical with the blue shift developing fully as low lattice temperatures are reached in hole distribution.

Photoreflectance measurements were used to investigate hole-subband structures in GaAs/InxAl1-xAs strained layer superlattices. The results showed that the indium concentration and the layer thickness had a significant effect on the subband order. The balance of the tensile-strain and quantum size effects that operate on the order determined the hole-subband order.

The interaction of a dislocation with an elliptic hole or rigid inclusion in an anisotropic material was investigated. The results showed that the level curve of the interaction energy in dislocations very near the elliptic boundary was similar in shape to the elliptic boundary. However, this was not the case when the dislocation was far from the elliptic boundary. For dislocations with Burger vectors in the circumferential direction, the interaction energy was not dependent on the orientation of the dislocation position.

The effect of the axially varying quasi-Fermi-level separation of the active region on spatial hole burning in distributed-feedback semiconductor lasers was investigated using a numerical model. The results showed that the influence of the longitudinal spatial hole burning on the static characteristics of quarter-wave-shifted distributed-feedback lasers was weakened by a current density injected into the active region.

A study was conducted on the effective masses of the valence bands and the electron hole mobilities of strained Si1-xGex layers on (001) Si1-yGe substrate. Results show that all the directional masses excluding the longitudinal heavy hole at the point where k=0 (based on k.p and strain Hamiltonians) are greatly affected by the strain. Large k values were found to weaken the strain effect. Further observations also attributed the anisotropic shift of the mobility of the strained layer to strain.

A proposed metal oxide semiconductor (MOS)-gated power device is tested using devices produced according to standard double-diffused MOS (DMOS) processes. Results show that the Minority Carrier Injection Controlled Field-Effect Transistor (MICFET) device at 500 Volts yields a 30% decrease of the on-state resistance as compared to the DMOSFET with turn-off occuring at less than 100 nanoseconds. The MICFET device is significatn to high-frequency power supplies.

Deep level transient spectroscopy was used to investigate deep levels of vanadium and vanadium-hydrogen complex in n- and p-type silicon. The results showed that two electron traps of -0.20 eV and -0.45 eV and a hole trap of 0.34 eV were present in the material. The three traps corresponded to the transitions between four charge states of interstitial vanadium. In addition, an electron trap of -0.49 eV was present near the surface region of the n-type silicon etched with an acid mixture containing HF hydrofluoric acid and HNO3 nitric acid.

Hole injection and trapping in the gate oxide region of an n-channel metal oxide semiconductor field effect transistor is studied under conditions of liquid-nitrogen temperature, high drain bias and low gate bias. It is found that channel hot-carrier injection is decreased by approximately one-third at 77 K in contrast to 295 K. The phenomena is attributed to lower hole mobility in SiO2 at cryogenic temperatures.

Deep level parameters are obtained from zinc-doped indium selenide (InSe) single crystals via resistivity, Hall effect and space-charge-limited-current measurements as well as photoinduced-current transient spectroscopy. Resistivity and Hall effect measurements showed that the samples examined are p-types within the temperature range 200 and 350 Kelvin. Resistivity and hole density are also examined as functions of temperature. Meanwhile, the activation energy of the acceptor level is at 0.59 electronvolt. Theoretical calculations and verification on transient currents are given while trap distribution energy gap of the Zn-doped InSe crystals is analyzed.

Majority and minority electron and hole mobilities are theoretically calculated in silicon at 300 Kelvin using the derived scattering and mobility expressions. The expression for low-field mobility is presented with theoretical considerations of several scattering mechanisms. The carrier energy and angular dependencies of the scattering rates due to ionized impurities are compared in terms of their Born approximation and quantum-mechanical phase shift expressions. Meanwhile, these scattering and mobility expressions are used in the silicon calculations and the results are found to be in agreement with the experimental mobility data for silicon.

A new approach is introduced for the solution of coupled transport equations modeling carrier flow in a double-carrier-multiplication avalanche photodiode (APD) of arbitrary geometry. The method, which provides the time and frequency response of such devices, is applied to two separate/absorption/grading/multiplication APDs and to a multiquantum-well APD. It may also be employed to measure the dark current and hole accumulation at the heterojunction interface.

A response is given to an earlier published work on the electron and hole traps induced by hole injection during hot-carrier stressing of n-channel metal oxide semiconductor transistors. It is claimed that the conclusions regarding neutral electron trap generation have no supporting evidence from experiments or research. Data presented in the article and earlier work on the subject are cited to support the claim. A reply by the authors is also presented.

The alpha and beta impact ionization coefficients for electrons and holes in pseudomorphically strained In0.2Ga0.8As and In0.15Ga0. 63Al0.22As channels embedded in Al0.3Ga0.7As were determined. The results showed that the impact ionization coefficients in lattice matched GaAs layers were lower than those in strained materials. In all samples investigated, the beta coefficient was larger than the alpha impact ionization coefficient.

Interband tunneling from a two-dimensional electron gas to a two-dimensional hole gas was investigated. The results showed that the tunneling current was inversely proportional to the lifetime of the states occupied in the two dimensional gas by tunneling. The temperature dependence of interband tunneling became more pronounced when the temperature was lowered. Tunneling assisted by phonon adsorption disappeared when decreasing spacing was at 5 nm.

Electron hole capture at the DX(Si) and DX(Te) defects in AlxGa1-xAs was investigated. The results showed that the DX centers associated with silicon and tellerium have large hole capture cross sections and were not affected by temperature. Extremely large electron capture cross sections related to high temperatures were observed. The DX center at higher temperatures was found to be an effective electron hole nonradiative recombination center.

Minority-carrier transport parameters are derived for p+-n gallium arsenide solar cells with a p+-layer doping density between 6.3 times 10 to the 17th power and 1.3 times 10 to the 19th power per cubic cm. The variables facilitate the determination of the electrical bandgap narrowing effect and the surface recombination velocity of bipolar devices. A comparison of equilibrium minority carrier concentration models shows the significance of considering bandgap shrinkage during simulation of heavily doped devices.

A combination of the reverse recovery time method and scanning electron microscopy was employed in separately determining n-layer electron and hole lifetimes of silicon p+-n-n+ diodes. The lifetimes were obtained from the measured values of reverse recovery time and electron-beam-induced junction currents. Results show a near unity value of electron-hole lifetime ratio for nonirradiated samples while electron-irradiated samples indicated a ratio value between seven to nine.

A study of charge carrier dynamics, both free and trapped, under nonequilibrium circumstances is presented. The Shockley-Read technique is employed to formulate a set of four differential equations to model thermal charge generation and recombination rates of electrons and holes in both states. They equations model the time-dependence behavior of such charge carriers in the mobility gap of amorphous semiconductors.

An emissive exciplex formed between an electron-accepting discotic material (hexaazatrinaphthylene (HATNA-SC12)) and a hole accepting conjugated polymer {poly[9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine] or TFB} is described. The studies have shown that the exciplex is strongly localized at the interface, which has acted as an energy bottleneck with inefficient transfer to bulk exciton states and with low yield of charge separation.

The positive magnetoresistance (PMR) was modulated by tuning the quantum interference effect (QIE) intensity via external electric field and control the hole density in the manganite/titanate p-n junction. The maximal PMR obtained by tuning the hole density via the bias voltage within 2 V demonstrates that the carrier density strongly affects the QIEs in the manganites.

The contribution of molecular environment to the exchange reactions in the DNA molecule is examined by considering different geometries of the reaction centers in oxidized and reduced states. Each counterion has contributed to the oxidation potential of the 7-8 nearest nucleosides and the irregularity due to phosphate neutralization has not modified the potential profile for the hole migration through the DNA molecule.

A detailed study is conducted on the hole transport in a polyspirobifluorene homopolymer and a statistical polyspirobifluorene-triarylamine copolymer employing the charge-generation layer time-of-flight (TOF) technique over a wide range of electric fields and temperatures. Results are analyzed within the framework of the Gaussian disorder model and the charge transport parameters are extracted for both polymers.

A method for fabricating induced two-dimensional hole devices in (311)A GaAs is demonstrated. This method uses a metallic p(super +)-GaAs capping layer thereby allowing very small gate biases to be used to induce a two-dimensional hole system at a AlGaAs/GaAs interface.