摘要:

The derivative Raman spectral method using an electro‐optically tuned laser is shown to be highly sensitive, can pick out weak and narrow spectral features hidden in a broad fluorescence background, and, most importantly, can detect extremely small shifts in the peak relative to the linewidth of the Raman‐scattered light.

ISSN:0003-6951    

DOI:10.1063/1.90539

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A flashlamp‐pumped coumarin dye laser mode locked passively with a saturable absorber 3,3′‐dihexyloxacarbocyanine iodide (DOCI) has produced tunable picosecond pulses shorter than 10 ps in the blue region of the spectrum between 475 and 490 nm. A single pulse switched from the train was used for fluorescence lifetime measurements. The excited‐state lifetime &tgr; of DOCI in pure ethyleneglycol was 505±10 ps.

ISSN:0003-6951    

DOI:10.1063/1.90540

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Rate constants for transfer between XeF(III,1/2) and XeF(II,3/2) states and quenching of XeF(III,1/2) have been measured using a method which employs the steady‐state photolysis of XeF2. For He, Ne, Ar, Kr, N2, CF4, and SF6transfer dominates over quenching; for Xe, NF3, CF3Cl, and CF3H quenching and transfer are competitive. Only for F2is quenching dominant. Based upon the relative emission intensities from XeF(III,1/2) and XeF(II,3/2) at high pressures of buffer gases, XeF(II,3/2) must be 0.08 eV lower in energy than XeF(III,1/2).

ISSN:0003-6951    

DOI:10.1063/1.90541

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Using Nd‐YAG laser pulses in the 100‐&mgr;s regime, melting and regrowth of monocrystalline silicon is studied. It is shown that surface melting proceeds preferentially along the crystallographic axes. This leads to a characteristic surface pattern if uniform irradiation slightly above melting threshold is applied. Regrowth under these circumstances is epitaxial.

ISSN:0003-6951    

DOI:10.1063/1.90542

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

An Auger in‐depth analysis and a 350 keV He+backscattering technique were used to investigate the growth of an SiO2protective layer and the compositional change in sputtered molybdenum silicide films after oxidation, respectively. Silicon depletion and molybdenum pileup in molybdenum silicide were observed near the SiO2/Mo‐Si interface. The film becomes molybdenum rich with increasing oxidation time. The Si/Mo atomic ratio decreases rapidly in the first 30‐min period and then decreases slowly, nearly proportionally to the square root of the oxidation time. These behaviors are explained by the preferential oxidation of silicon and the reduced silicon present at the SiO2/Mo‐Si interface from the rest of the molybdenum silicide layer.

ISSN:0003-6951    

DOI:10.1063/1.90543

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Annealing behavior of phosphorus‐implanted silicon layers underQ‐switched Nd3+‐YAG laser irradiation was examined for samples with various dose (1014−1016cm−2). Annealing efficiency in the implanted layer was found to be strongly influenced by the degree of damage to the substrate, namely, the annealing effect was localized to the amorphous regions. This selective annealing of the amorphous region was explained by the difference in the absorption coefficient of laser energy between crystalline and amorphous silicon.

ISSN:0003-6951    

DOI:10.1063/1.90544

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Single grain‐grain junction measurements of the current‐voltage characteristic of ZnO ceramic varistors are interpreted in terms of electron transmission through depletion layer barriers at the ZnO grain interface. The highly nonlinear varistor conduction process is associated with an abrupt thinning of the ZnO depletion layer due to valence‐band hole injection when the bottom of the ZnO conduction band in the grain interior drops below the top of the valence band at the grain surface.

ISSN:0003-6951    

DOI:10.1063/1.90545

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Quantization of ion microprobe mass spectrometric analyses has been complicated by the variation in the ion yield of an element contained in different matrices. This work demonstrates that, for O−and Cs+bombardment, these ion‐yield variations are solely attributable to variations in the matrix sputtering yield. It is argued that the matrix sputtering yield determines the near‐surface concentration of the ion‐yield‐enhancing species O and Cs.

ISSN:0003-6951    

DOI:10.1063/1.90546

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A laser‐Doppler anemometer based on a continuous GaAlAs diode laser source is described. It is shown that the coherence length of the diode output requires that the optical design incorporate equal path lengths for good fringe visibility. The results show that Doppler signals of processable quality may be obtained using this compact laser source.

ISSN:0003-6951    

DOI:10.1063/1.90547

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

We report a new material for self‐contained all‐solid‐state electrochromic devices with fast response. The material is phosphotungstic acid (PWA) which, at room temperature, is both an electrochromic material and an ionic conductor. Response times of 50 msec have been measured in cells of typeM/PWA/SnO2, whereMdenotes an electrode that provides ions of Ag, Cu, or Li. The cell exhibits memory.

ISSN:0003-6951    

DOI:10.1063/1.90548

出版商:AIP    

年代:1978

数据来源: AIP