Ga doping

A technique known as selective electron capti sensitization has been used to increase the response of the BCD weakly electron-capturing compounds [117]. In this mode a standard electron-capture detector is used with a supply of makeup gas doped with a specific sensitizing reagent such as oxygen nitrous oxide. In this way the BCD functions as an ion-aoleculSj... 

The most detailed NMR study of impurity band formation in a semiconductor in the intermediate regime involved 31P and 29 Si 7). line width and shift measurements at 8 T from 100-500 K for Si samples doped with P at levels between 4 x 1018 cm 3 and 8 x 1019 cm 3 [189], and an alternate simplified interpretation of these results in terms of an extended Korringa relation [185]. While the results and interpretation are too involved to discuss here, the important conclusion was that the conventional picture of P-doped Si at 300 K consisting of fully-ionized donors and carriers confined to extended conduction band states is inadequate. Instead, a complex of impurity bands survives in some form to doping levels as high as 1019 cm 3. A related example of an impurity NMR study of impurity bands is discussed in Sect. 3.8 for Ga-doped ZnO. 

Acenaphthene was detected in a diesel-powered medium duty truck exhaust at an emission rate of 19.3 pg/km (Schauer et ah, 1999) and is a component in cigarette smoke. Acenaphthene was detected In soot generated from underventilated combustion of natural gas doped with 3 mole % toluene (Tolocka and Miller, 1995). 

Fluorene was detected in soot generated from underventilated combustion of natural gas doped with toluene (3 mole %) (Tolocka and Miller, 1995). 

Magnetic transition in pure and Ga doped a-Fe20j. Phys. Lett. 7 177-178 Morrison, S.J. Spangler, R.R. V.S. Tripathi (1995) Adsorption of uranium(VI) on amorphous ferric oxhydroxide at high concentrations of dissolved carbon(lV) and sulfur(VI). 

Germanium, gallium-doped grid (Ga-doped Ge grid), AG08... 

Fig. 2.8. (a) Hall mobility as a function of the temperature for an undoped epitaxial ZnO layer and (b) Hall mobility of Ga-doped ZnO layers as a function of the carrier concentration. The ZnO films were grown epitaxially on lattice-matched ScAlMg04 (SCAM) by Makino et al. [64], In (a) the calculated mobilities for acoustical, polar-optical, piezoelectric, and ionized impurity scattering are shown, together with the total theoretical mobility. In (b) the solid curve is the fit curve (2.24) from Fig. 2.6, while the dashed line is the theoretical curve, calculated by Makino et al. [64]. The dotted line was calculated for transport across depletion regions at grain barriers (see Sect. 2.2.3), also present in epitaxial films [106]... 

Fig. 3.16. Experimental (dotted lines) and best-model calculated (solid lines) IRSE spectra of PLD-grown Ga-doped ZnO thin films on sapphire with different free-charge-carrier concentration and thickness parameters as indicated next to the respective graphs [43]. Spectra are shifted for clarity...

The experimental IRSE data were analyzed assuming an isotropically-averaged effective electron mass parameter of m = 0.28me [135].6 Thereupon, the free-charge-carrier concentration N and the optical mobility parameters p,°pt (i =, L) were obtained [43]. The results of the IRSE-analysis of two sets of Ga-doped ZnO thin films are summarized in Fig. 3.18. 

Fig. 3.18. Free-charge-carrier concentration (a,b) and mobility parameters (c,d) of Ga-doped ZnO thin films on sapphire vs. oxygen pressure during PLD-growth [43]. Triangles and circles correspond to the results determined by IRSE and Hail-effect measurements, respectively. Panels (a,c) and (b,d) contain the results of the films grown with 0.1 and 0.5 mass percent Ga2C>3 powder within the PLD target, respectively. Up- and down-triangles in panels (c) and (d) represent the anisotropic optical mobility parameter /inpt and respectively...

Concerning the free carrier mobility, it has been observed that, except for very low doping ratios (e.g., fluorine content <0.4 at. % for AP-CVD ZnO F or gas doping ratio B2He/DEZ<0.2 for the LP-CVD ZnO B), p continuously decreases when the doping ratio is increased. This is attributed to the following ... 

Fig. 6.41, where one can note a progressive drop of the transmittance curves with increase in B2H6/DEZ gas doping ratios. 

Fig. 6.45. Carrier mobility // of various LP-CVD ZnO B samples deposited at IMT Neuchatel as a function of the grain size parameter S. The doping series is the one for which the gas doping ratio B2H6/DEZ has been varied. The doped and undoped series are those for which doped and undoped ZnO films were deposited under a variation of deposition parameters, like substrate temperature or gas ratio HaO/DEZ...

One of the key experiments [38] that has helped to elucidate the different temperature dependencies in HTSC s is the controlled study on undoped, as well as on Zn and Ga doped Y 1 2 3. Figure 8.5 shows the results of the experiments on Y 1 2 3 doped with various levels of Zn. It is seen that the decrease in bulk lifetime seen in undoped Y 1 2 3 reverses to an increase in lifetime in Zn doped Y 1 2 3. The variation of lifetime in all the cases is seen to be correlated with Tc, which decreases with increase in Zn content. In the following, we show [39] that the different temperature dependencies in undoped and Zn-doped Y 1 2 3 are related to the difference in the positron density distribution with respect to the superconducting Cu-0 planes. 

Commercial n-type 6H-SiC wafers with a concentration of uncompensated donors Nd - Na = 3x lO cm were used as substrates. These substrates were covered with a thin epitaxial n-GaN buffer layer grown by hybrid vapor phase epitaxy (HVPE). This buffer layer had a thickness of 0.2 pm and a donor concentration of Nd-Na = (2-3)xl0 cm . On top. Mg doped / -type AlGaN epitaxial layers with thickness of 0.8 pm and an Al content of 12 at.% were also grown by HVPE with an acceptor concentration of Na-Nd = (5-8)xl0 cm. Then, Ga doped n-ZnO epitaxial layers were deposited using chemical vapor deposition (CVD) with a thickness of 0.8 pm and a donor concentration ofNd - Na = 7xl0 cm. The growth process was stimulated by a discharge plasma, that allowed to reduce the substrate temperature by up to 400 °C and thus improve the structural quality of the ZnO layers. ... 

The products of the reactions of silanetriols with gallium [41] and indium alkyls [42] are very similar to those obtained from aluminum alkyls described above. The interest in Ga containing siloxanes stems from the known catalytic activity of Ga-doped zeolites in the dehydrogenation reactions of alkanes. The reactions of silanetriols 15 and 16 with GaMej or InMes in refluxing hexane/1,4-dioxane lead to the cubic Ga/In siloxanes [RSi03M-THF]4 (M = Ga 38, 39 In 40, 41), respectively. In the resulting products, the Ga and In centers are coordinated to a dioxane solvent molecule These compounds have a very similar structure to that of aluminosiloxanes 30-33 shown in Scheme 7. 

Table 9.2. Electrical properties of epitaxial layers with Ga doping versus solvent and cooling rate. Growth temperature was 1,050°C [69]...

Fig. 10.6. Temperature dependence of growth rates of silicon (from, precursor 1% of dichlorosilane in H2). Filled diamond no gas doping, filled square B2H6, filled circle PH3, filled triangle ASH3 [16]...

The results of piezospectroscopic measurements on the Al-X spectrum are consistent with a trigonal <111> oriented centre [33]. Early measurements of the X-centre concentration showed no dependence on the concentration of interstitial oxygen, but a linear dependence on [Cs] which led to their attribution to (C, acceptor) pairs [85], However, subsequent measurements on NTD Ga-doped FZ silicon with undetectable [Cs] showed the presence of Ga-X centres after annealing at 450-550°C [145] so that the atomic structure of these centres is still an open problem. Calibration factors for lines l(B-X), 2(AZ-X), 2(Ga-X), and 2(In-X) given by Jones et al. [85] are 1.1, 2.5, 2.5, and 28 x 1013 cm-1, respectively. 

Magnetoacoustic resonance attenuation measurements in Ga-doped germanium at LHeT in the range 0-12 T have allowed [142] to measure the -factors of the ground state of this acceptor, including two of the q quadratic terms of expression (8.22). The values thus obtained are ... 

PREPARATION OF Ga-DOPED ZEOLITE CATALYSTS VIA HYDROGEN INDUCED SOLID STATE INTERACTION BETWEEN Ga2°3 HZSM-5 ZEOLITE... 

Fig. 5.13 (a) In a p-type semiconductor (e.g. Ga-doped Si), electrical conductivity arises from thermal population of an acceptor level which leaves vacancies (positive holes) in the lower band, (b) In an n-type semiconductor (e.g. As-doped Si), a donor level is close in energy to the conduction band. 

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