摘要:

The grain boundary trap state density is evaluated in polysilicon thin‐film transistors by a method based on the dependence of the grain boundary potential barrier height on the gate voltage. Assuming a Gaussian energy distribution of the grain boundary trap states, the distribution parameters are determined by fitting the grain boundary barrier height experimental data with the theory. In low‐pressure chemical vapor deposited polysilicon films, the influence of deposition pressure on the grain boundary trap distribution is examined by using this method. A large number of traps exist at the grain boundaries near the midgap of the material deposited at lower pressure due probably to an increased impurity contamination.

ISSN:0021-8979    

DOI:10.1063/1.352836

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

Core and valence level photoelectron spectra demonstrate that the deposition of monatomic interlayers at the interface between CdS and InP(110) efficiently suppresses the interface reaction characteristic for this system, and has a marked influence on the valence‐band offset &Dgr;Ev.

ISSN:0021-8979    

DOI:10.1063/1.352837

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

The effects of Te codoping in ZnS:CeF3thin‐film electroluminescent devices are reported. ZnS1−xTex:CeF3thin films are prepared at several Te concentrations and substrate temperatures. The emissive peak position and intensity depend on Te concentrations, substrate temperatures, the annealing, and drive voltages.

ISSN:0021-8979    

DOI:10.1063/1.352838

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

We have investigated the doping incorporation and activation of InP growth using metalorganic chemical vapor deposition on <100≳, <311≳B, and <110≳ InP substrates. Effects of orientation, growth temperature, and V/III fluxes were studied. The dopants used were Zn from dimethylzinc [(CH3)2Zn] and diethylzinc [(C2H5)2Zn], S from hydrogen sulfide [H2S], Si from silane [SiH4], and Sn from tetraethyltin [(C2H5)4Sn]. The incorporation and activation of thep‐type dopant Zn are elevated on the <311≳B and <110≳ planes, while the incorporation is suppressed for then‐type dopants (S, Si, and Sn). Then‐type dopant Sn has similar incorporation and activation on the various substrate orientations studied. Anomalous Zn doping on the higher order planes <311≳B and <110≳ lead to the Zn incorporation exceeding the solubility limit in InP. Incorporated Zn levels as high as 1.0×1019cm−3were measured, and the corresponding activated Zn level was as high as 5.4×1018cm−3on a <110≳ InP substrate. Interdiffusion of thep‐type dopant Zn into the S‐dopedn‐type InP substrate is inhibited by a high S‐doping level and segregates at the substrate–epilayer interface. If the S‐doping level is lower than the Zn concentration, then Zn diffuses deep into the substrate at a uniform level.

ISSN:0021-8979    

DOI:10.1063/1.352839

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

Remote plasma activated chemical vapor deposition (RPACVD) is an attractive fabrication technique owing to the increased selectivity of radical generation which can be obtained compared to deposition techniques in which the substrate is immersed in the plasma. This selectivity can be compromised if the deposition gases, which are typically injected downstream of the plasma zone, back‐diffuse into the plasma where indiscriminate electron impact dissociation occurs. In this communication, a new RPACVD technique is described in which the plasma and injected gases are sequentially pulsed to temporally isolate the injected gases from the plasma. This method reduces, or eliminates, indiscriminate dissociation of the injected gases and improves the selectivity of radical fluxes to the substrate.

ISSN:0021-8979    

DOI:10.1063/1.352840

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

The electronic bands of BaB2O4(BBO) and LiB3O5(LBO) have been computed from first principles using theabinitiopseudofunction method. Optical conductivities and densities of states in good agreement with optical measurements and x‐ray photoemission are obtained. The gap in BBO results from the borate group to the Ba. In LBO, the gap is from a fourfold coordinated borate to a threefold coordinated borate. This suggests that cluster calculations based on the borate groups alone is a reasonable approximation for LBO, but not for BBO.  

ISSN:0021-8979    

DOI:10.1063/1.352841

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

Thin films of the europium monochalcogenides, EuS, EuSe, and EuTe, have been produced using pulsed laser deposition on to heated quartz substrates. The films show a high degree of orientation of the (001) planes parallel to the substrate. In optical absorption, the shift of the band edge on cooling below their Curie/Ne´el temperatures is clearly seen.

ISSN:0021-8979    

DOI:10.1063/1.352842

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

Thin metallic, oriented crystalline NiSi2films that are suitable for additional epitaxial growth have been formed on amorphous SiO2layers on Si substrates. The orientation of the Si substrate is maintained in the NiSi2film as if the SiO2is not present. This was achieved by combining the separation by implantation of oxygen process ande‐beam evaporation techniques. The results are comparable with NiSi2films formed directly on Si. This technique should, in general, be applicable to other silicides that have been epitaxially grown on Si.

ISSN:0021-8979    

DOI:10.1063/1.352843

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

The launching and propagation of Lamb waves in magnetostrictive polycrystalline ferrite plates was studied. The influence of a magnetic overlay situated parallel to the surface of the plate in the vicinity of the meander‐type transducer on the efficiency of the transducer was investigated. The results obtained show that Lamb wave velocities are more sensitive to magnetic fields than Rayleigh wave velocity, and that the use of a magnetic overlay essentially improves the efficiency of the meander type transducer.

ISSN:0021-8979    

DOI:10.1063/1.352844

出版商:AIP    

年代:1993

数据来源: AIP