摘要:

The photo‐induced shift in the optical transmission edge has been studied in obliquely deposited amorphous Se75Ge25films. The effect of preannealing, exposure, postannealing, and film thickness on the photo‐induced optical changes have been investigated. Our studies reveal that the photoeffects consist of two distinct contributions: photothermal and photo‐optical. Whereas the photothermal effect decreases with angle of deposition as well as annealing, the optical effect increases rapidly with obliqueness. The nature and the respective contributions of these two processes have been established.

ISSN:0021-8979    

DOI:10.1063/1.325639

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Primary‐ion charge compensation by means of simultaneous bombardment of the insulating specimen with a focused beam of low‐energy electrons has been investigated. The measurements were performed in a quadrupole‐type SIMS instrument which allowed the amount of charging to be measuredinsitu. The effectiveness of charge neutralization was investigated by monitoring the intensity, the mass resolution, and the line shape of both (positive) atomic and molecular secondary ions. It was found that in the range of electron energies investigated (100–500 eV) the energy has little effect on the amount of charge neutralization (for bombardment of a gadolinium iron garnet sample with 12‐keV argon ions). A well‐defined minimum electron current was required to provide compensation of the primary ion charge. ’’Supersaturation’’ with electrons caused only a negligible reduction in signal height. Studies with focused ion beams showed that effective neutralization requires compensation of the local primary ion current density. In case of current density compensation the mass resolution observed with insulating specimens is as good as for metals or semiconductors. Possible mechanisms of charge compensation are discussed briefly.

ISSN:0021-8979    

DOI:10.1063/1.325640

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

High‐voltage‐radiation photographs, otherwise known as Kirlian photographs, are normally obtained as contact prints on photographic film or paper. However, the same kind of images can be formed by high‐voltage corona discharges on bulk dielectrics and on thin films of various materials deposited on glass substrates. The transport of thin‐film materials has been observed, accompanied by the formation of droplets in the case of oily films. Moisture released by objects of living and unanimated matter is directly recorded on some thin films.

ISSN:0021-8979    

DOI:10.1063/1.325641

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Compositionally modulated single‐crystal InSb/GaSb superlattice structures have been grown by multitarget sputtering in order to investigate the effects of film growth parameters on the defect structure, abruptness, and coherence of sputtered heterojunctions. The layer thicknesses studied ranged from 12 to 70 A˚. The polycrystalline–to–single‐crystal ’’transition temperature’’Tcwas found to decrease with decreasing average film‐substrate lattice mismatch and modulation period, &Lgr;. The &Lgr;‐dependence resulted from a decrease in the coherence between layers and the associated increased amount of plastically accommodated strain which occurred with increasing layer thickness. Increasing the film growth temperatureTSand decreasing the period of the composition modulation also resulted in a decrease in the density of microtwins and low‐angle dislocation boundaries which were observed in all films. Single and multiple {111} twins were identified. For a given set of growth conditions on cleaved BaF2and NaCl substrates, a significant decrease inTcand structural defect densities could be achieved by coating the substrates with thin (<300A˚) single‐crystal InSb layers which were deposited and annealedinsituimmediately prior to superlattice film growth. Variations inTSbetween 150 and 320 °C had no effect on either the amplitude of composition modulation in deposited films or on the minimum layer thickness &Lgr;minobtainable from a given set of sputtering conditions. &Lgr;minwas, however, found to be dependent on the sputtering pressure and was limited by ion‐bombardment‐enhanced diffusion during film growth. A model is discussed for determining bombardment‐enhanced diffusion coefficientsD* as a function of growth conditions using measured x‐ray superlattice diffraction intensities. Values ofD* obtained in this way were several orders of magnitude larger than thermal diffusion coefficients found from postannealing experiments.

ISSN:0021-8979    

DOI:10.1063/1.325643

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Solutions of the differential equation satisfied by the circularly symmetric electric fieldE&fgr;in an azimuthally magnetized ferrrite cylinder are given in terms of two infinite series which reduce to Bessel functionJ1(x) and Neumann functionN1(x) in the absence of the dc magnetic field. These results differ from the solutions which have been used in literature associated with ferrite‐rod phase shifters. A numerical table is provided for the comparison between the present and the former solutions.

ISSN:0021-8979    

DOI:10.1063/1.325644

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The various noise contributions of an rf SQUID have been studied. The importance of the noise figure of the rf amplifier has been pointed out by calculation and experiments, particularly by using a cooled GaAs FET preamplifier (noise temperature 25 K at 300 MHz) we have designed. The effects of noise upon the flux‐locked loop characteristic have been investigated by introducing the notions of unlocking probability and of unlocking average time; the improvement of performances, especially of the slew rate of the flux‐locked system by an increase of the modulation frequency, is limited by the noise.

ISSN:0021-8979    

DOI:10.1063/1.325645

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

An analysis has been made for the high‐field domain dynamics in a planar Gunn diode, based on stroboscopic observations by a scanning electron microscope. The 1‐GHz pulsed electron beam was synchronized with the microwave‐triggered oscillating diode. The movement of the domain could be clearly observed. The domain dynamics is discussed in detail, taking the time fluctuation in microwave triggering into account. The experimental results are also supported by a theoretical analysis.

ISSN:0021-8979    

DOI:10.1063/1.325646

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The comment of Viviani and Viviani concerning the old riddle of unipolar induction and the M (moving) and N (nonmoving) hypotheses contains a contradiction.

ISSN:0021-8979    

DOI:10.1063/1.325647

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Differentiated electron‐beam‐induced current (DEBIC) is shown to be well suited for the study of semiconductor heterostructure lasers. The DEBIC signal, unlike the standard EBIC signal, is rich in fine‐structure information in the vicinity of the active region. A simple model is introduced to explain the characteristic DEBIC signal. As a result of the anisotropy of the carrier distribution, higher spatial resolution (≲0.2 &mgr;m) is achieved with DEBIC than with the standard technique, EBIC (?1 &mgr;m). The DEBIC can be used to obtain diffusion lengths of the minority carriers and to evaluate the quality and uniformity of the device fabrication.

ISSN:0021-8979    

DOI:10.1063/1.325648

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

GaAs wafers were implanted with sulfur or silicon ions and annealed at temperatures from 800 to 950 °C under arsenic partial pressure controlled by arsine (AsH3) flow. Electrical characteristics obtained in this method were nearly identical or superior to those obtained with dielectric films. No sign of surface deterioration was observed even after annealing at 950 °C. The implantation into a Cr‐doped epitaxial layer resulted in better characteristics than into semi‐insulating substrates from a vender. The best doping efficiency of 89% was obtained with a dose of 1×1013Si+/cm2. The method is simple and reproducible, and suitable for the annealing process in production.

ISSN:0021-8979    

DOI:10.1063/1.325649

出版商:AIP    

年代:1979

数据来源: AIP