摘要:

An efficient and reliable simulator has been developed which solves the Poisson, continuity, and Schro¨dinger equations self-consistently to obtain the current-density–voltage characteristics ofn-type semiconductor field emitters of electrons. The one-dimensional simulator takes into account the multidimensional geometry dependent-field variation near the semiconductor tip. The results obtained show the effects of the semiconductor parameters such as electron affinity, effective mass, mobility, and dielectric constant on the emission characteristics. The doping concentration is found to have a strong influence on the emitted current. The emission characteristics show deviations from linearity in a Fowler–Nordheim-type plot especially at high currents. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121019

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Electroluminescence (EL) and electrophysical characteristics of erbium and oxygen coimplanted and annealedp–njunctions, characterized by higher values of theEr3+-related EL intensity at∼1.54 &mgr;min the breakdown regime at 300 K as compared with that at 85 K, have been studied in the temperature range from 85 to 300 K. Hole traps in the Er–O codopednlayer were found to be responsible for the anomalous EL behavior. Er-related EL was observed in the same samples in avalanche breakdown at high temperatures and in tunnel breakdown at low temperatures. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121020

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Heavy doses of radiation in space can cause the failure ofn+/p/p+silicon solar cells due to the gradual introduction of compensating defects into the base layer of the diode. In this letter, we show that the radiation-induced defects, which play the most important role in this process, referred to as “carrier removal,” are probably minority-carrier traps at an energy level approximately 0.18 eV below the conduction band. We conclude that these defects must be positively charged before electron capture, and therefore, act as donor centers which compensate thep-type base layer. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121021

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

In this letter we present a device, based on amorphous silicon material, able to detect infrared light through capacitance measurement at room temperature. The device is ap-c-nstacked structure, wherecindicates a compensated amorphous silicon absorber layer. Operation is based on transitions between extended states in the valence band and defects in the forbidden gap excited by the infrared radiation. We found that the measured capacitance is sensitive to radiation from 800 nm to 5 &mgr;m. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121022

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Isotropic features with hyperfine structures in electron paramagnetic resonance spectra of SrS powder phosphors, which reflect the abundance of the natural Cr isotopes, are attributed to the isolated Cr impurity. The isotropy, which is typical for a4A2ground state of a3d3ion in an octahedral crystal field, and thegvalue of 1.9795 verify that Cr is observed in its charged donor stateCr3+.The observation of a broad photoluminescence band with a maximum at 900 nm, which can be attributed to an internalCr3+transition, supports the identification of the impurity asCr3+.©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121023

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Carbon doping of epitaxial InSb films grown by gas-source molecular beam epitaxy was studied using carbon tetrabromide as the carbon dopant source. Carbon was found to be ap-type dopant in InSb, yielding the highest as-grown acceptor concentrations to date, up to mid1020 cm−3as deposited. Room temperature mobilities ranged from 35 to90 cm2/V sdepending upon doping level. The hole concentration was found to be relatively insensitive to growth temperature between 325 and 400 °C. Higher growth temperatures required higher Sb fluxes in order to maintain a constant hole concentration. Hole concentration increased linearly with increasingCBr4up to5×1020 cm−3.Further increase in the dopant flow reduced the hole concentration and mobility and produced polycrystalline material. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121024

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We have used atomic force microscopy to investigate the surface morphology of ZnSe films grown on GaAs(001) by molecular beam epitaxy. We report the observation of nanometer scale surface clusters 400–1200 Å in diameter and 60–200 Å in height. The clusters formex situas the result of the initial exposure of the ZnSe to atmosphere, and undergo Ostwald ripening at room temperature. Our observations, combined with the relevant literature, suggest that the cluster composition isSeO2.We propose that the oxidation of the ZnSe epilayers produces a thin layer ofSeO2which migrates to form surface clusters on a stable, zinc-related oxide surface. These findings should facilitate greater control of surface morphologies during ZnSe based device fabrication processes.

ISSN:0003-6951    

DOI:10.1063/1.121025

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

(Ba,Sr)TiO3(BST) films were synthesized onBaRuO3(BRO) using radio-frequency magnetron sputter deposition. Conductive (∼1 m&OHgr; cm) BRO layers of (110) texture were produced at a deposition temperatureTd=400 °C,about 200 °C lower than that ofSrRuO3.The BST (100 nm) deposited on the BRO showed a (110) preferred orientation and crystallization formation at temperatures as low as 200 °C. An interfacial layer and the local epitaxial growth of BST on BRO layers within columnar grains were confirmed by high-resolution transmission-electron microscopy studies. UniformI–Vcharacteristics(I<1×10−7 A/cm2)for bias voltages in the range 0.0–3.0 V of all the BST films deposited withinTd=300–500 °Cwere observed. The dielectric constants of the BST films (e.g.,&egr;r=300atTd=400 °C)are considerably higher than those generally achievable for the sameTdby using Pt bottom electrodes. The dependence of the annealing atmosphere(N2andO2)of the dielectric constants was studied and attributed to a diffused BST/BRO interfacial layer which is semiconductive in a reduced state and insulating in an oxidized state. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121026

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The photoluminescence ofin situ-doped GaN:Er during hydride vapor phase epitaxy was compared to an Er-implanted GaN sample. At 11 K, the main emission wavelength of thein situ-doped sample is shifted to shorter wavelengths by 2.5 nm and the lifetime is 2.1±0.1 ms as compared to 2.9±0.1 ms obtained for the implanted sample. The 295 K band edge luminescence of thein situ-doped sample was free of the broad band luminescence centered at 500 nm which dominated the spectrum of the implanted sample. Reversible changes in the emission intensity of thein situ-doped sample upon annealing in aN2versus aNH3/H2ambient indicate the probable role of hydrogen in determining the luminescence efficiency of these samples. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121034

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The effect of fluorine onSiO2films was investigated by comparing chemical and electrical properties of fluorinated silicon oxide (SiOF) films with those ofSiO2films. The SiOF films were prepared at room temperature by plasma enhanced chemical vapor deposition incorporatingCF4as the fluorine source into the deposition process of theSiO2films usingSi2H6andN2O.The relative dielectric constant of the as-depositedSiO2films was reduced from 5.95 to 4.43 by the incorporation of fluorine and with postmetallization anneal. The breakdown measurements on the SiOF films showed no early failures at a field strength of⩽3 MV/cm,resulting in an average breakdown field strength of 7.11 MV/cm. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121027

出版商:AIP    

年代:1998

数据来源: AIP