Highly Conductive And Transparent Amorphous Tin Oxide

The physical properties of chemically sprayed tin oxide films have been investigated. The optical and transport behavior of both amorphous and polycrystalline material depends on the reaction temperature. Amorphous films deposited at very low temperatures (Ts=220°C) possess a conductivity as high as that of the polycrystalline layers. Hall effect measurements and compositional analyses of those amorphous films show that nonintentional chlorine doping is responsible for the increased conductivity. Optical transmission in the visible region of the spectrum is almost as good in amorphous as in polycrystalline material. An antireflecting coating of amorphous tin oxide with an optical gain of 40% has been achieved on silicon wafers. Furthermore, film thickness homogeneity broadens the field of application to various optoelectronic devices.54143143

Indium And Gallium P-type Doping Of Hydrogenated Amorphous Germanium Thin Films

Hydrogenated amorphous germanium films have been p-type doped with indium and gallium. The room-temperature dark dc conductivity of the films has been found to change by several orders of magnitude within the studied dopant atomic concentration range (∼3×10 -5 to ∼1×10 -2). The conductivity change from n to p type for the more heavily doped materials indicates effective p-type doping. The hydrogen content and the optical gap of the doped films, on the other hand, remain essentially unchanged with respect to the undoped material. For the most doped samples, signs of metallic segregation have been detected in the case of gallium doping. Metallic segregation is not apparent for indium-doped samples.64243273327

BAND-GAP TAILORING IN AMORPHOUS GERMANIUM-NITROGEN COMPOUNDS

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Doping Effects In Off-stoichiometric Glow Discharge Amorphous Silicon Nitride

The effects of boron and phosphorus doping on the electrical properties of a-SiNx:H films are studied. The material is obtained by the glow discharge of SiH4 and N2 mixtures. It is found that for Si-rich materials boron doping produces large conductivity variations while phosphorus appears to be a much less efficient dopant. A phenomenological explanation is given assuming that phosphorus prefers to form bonds in accordance with its own valence configuration; i.e., it will go substitutionally to threefold coordinated N sites. Experimental evidence of such behavior obtained from published IR transmission measurements confirms this assumption.441116118IEEE Italy Sectio

TRANSPORT-PROPERTIES OF NITROGEN-DOPED HYDROGENATED AMORPHOUS-GERMANIUM FILMS

This paper discusses experimental data referring to the electronic properties of N-doped hydrogenated amorphous germanium films (a-Ge:H). The a-Ge:H films, prepared by rf sputtering, possess a low density of electronic states in the pseudogap (in the low 10(16) cm-3 range) and exhibit a temperature-activated dark conductivity down to below 200 K. It is shown that N atoms incorporated into the a-Ge:H films produce large changes of both the room-temperature dark conductivity and the activation energy. The results of the present work are consistent with the overall picture of the active doping mechanism of group-V elements in tetrahedrally coordinated amorphous semiconductors. The donor level introduced by fourfold-coordinated nitrogen in a-Ge:H is found to be around 50 meV below the conduction-band edge.4642119212

ON THE DOPING EFFICIENCY OF NITROGEN IN HYDROGENATED AMORPHOUS-GERMANIUM

This letter reports on the doping efficiency of nitrogen in a-Ge:H films of electronic quality. It has been found that nitrogen is an effective dopant in the a-Ge:H network, its doping efficiency being similar to the one corresponding to phosphorus in a-Si:H. The concentration of active nitrogen atoms decreases with impurity content following a square root dependence on total nitrogen. This behavior is similar to the one determined for column V dopants in a-Si:H films of electronic quality.621586

Structure And Composition Of Amorphous Ge1-xsnx Thin Films

The composition and bonding configuration of amorphous germanium-tin (a-Ge1-xSnx) thin films are reported (0≤x<0.3). Mössbauer spectroscopy analyses show that under the reported deposition conditions all tin atoms enter the a-Ge network in a perfect substitutional way, i.e., in a covalent tetrahedral configuration. The absence of defect structures in the tin sites is discussed and compared with results on films prepared under different conditions.63115596559

Nitrogen In The Amorphous-germanium Network: From High Dilution To The Alloy Phase

In this work experimental data referring to the structural and optoelectronic characteristics of amorphous-germanium-nitrogen thin films are presented and discussed. The nitrogen content of the a-Ge:N samples, deposited by the rf-sputtering technique in an Ar+N2 atmosphere, was allowed to vary from typical impurity levels (less than 0.5 at. %) up to around 35 at. %. The material properties change depending on the nitrogen concentration, determined from a deuteron-induced nuclear reaction. The likely mechanisms of nitrogen incorporation into the solid phase are discussed, as well as the influence of the nitrogen content on the transport and optical properties of the films. A proportionality constant relating the total nitrogen concentration in the solid phase and the integrated absorption of the in-plane stretching vibration mode of the Ge-N dipole has been determined. It has been found that a close analogy exists between the general properties of a-Ge:N alloys and those measured in amorphous-silicon-nitrogen alloys. © 1993 The American Physical Society.4874560457

NITROGEN IN THE AMORPHOUS-GERMANIUM NETWORK - FROM HIGH DILUTION TO THE ALLOY PHASE

In this work experimental data referring to the structural and optoelectronic characteristics of amorphous-germanium-nitrogen thin films are presented and discussed. The nitrogen content of the a-Ge: N samples, deposited by the rf-sputtering technique in an Ar+N2 atmosphere, was allowed to vary from typical impurity levels (less than 0.5 at. %) up to around 35 at. %. The material properties change depending on the nitrogen concentration, determined from a deuteron-induced nuclear reaction. The likely mechanisms of nitrogen incorporation into the solid phase are discussed, as well as the influence of the nitrogen content on the transport and optical properties of the films. A proportionality constant relating the total nitrogen concentration in the solid phase and the integrated absorption of the in-plane stretching vibration mode of the Ge-N dipole has been determined. It has been found that a close analogy exists between the general properties of a-Ge:N alloys and those measured in amorphous-silicon-nitrogen alloys.4874560457

USE OF HYDROGENATION IN THE STUDY OF THE PROPERTIES OF AMORPHOUS-GERMANIUM TIN ALLOYS

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