摘要:

Heavily doped ZnO:Al films were made by dual‐target reactive magnetron sputtering. Spectrophotometry in the 0.3–50 &mgr;m range proved that the films were suitable for energy‐efficient windows. The optical data could be reconciled with a theory involving a free‐electron gas damped by ionized impurity scattering.

ISSN:0003-6951    

DOI:10.1063/1.99008

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We report an experimental observation of a blue shift in then=1 heavy‐hole exciton line of In0.53Ga0.47As/InP multiple quantum wells resulting from a picosecond photoexcitation in the transparent spectral region. The temporal response of this shift follows the excitation and it is attributed to the optical Stark effect. The shift was measured to be 0.19 meV for an incident light with a photon energy 20 meV below the exciton peak and with a 10‐MW/cm2intensity.

ISSN:0003-6951    

DOI:10.1063/1.98905

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A hybrid growth technique has been used to fabricate low‐threshold, high‐modulation bandwidth, and high‐power 1.3 &mgr;m InGaAsP buried crescent injection lasers. The technique involves a first growth of an Fe‐doped semi‐insulating current confinement layer by low‐pressure metalorganic chemical vapor deposition followed by a liquid phase epitaxy regrowth. The lasers have cw threshold currents as low as 10 mA at 25 °C, total differential quantum efficiency over 50%, high‐temperature operation up to 100 °C, and output power more than 33 mW/facet. A 3‐dB modulation bandwidth of 8.4 GHz has been achieved at 5 mW/facet.

ISSN:0003-6951    

DOI:10.1063/1.98906

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A new technique for the nondestructive characterization of semiconductor heterostructures is presented. The technique consists of a measurement of the attenuated total reflection (ATR) spectrum of the structure. This spectrum is characterized by sharp interference patterns and deep resonance minima, corresponding to the excitation of various resonant modes. From the analysis of the ATR spectrum, detailed information can be obtained on the geometrical and compositional parameters of the structure. The technique, which is nondestructive and fast, is a natural candidate for general use in semiconductor technology (microelectronics, optoelectronics, integrated optics). To illustrate its potential, we discuss its application to the case of the thickness characterization of the wafers used to manufacture GaAlAs heterostructure lasers.

ISSN:0003-6951    

DOI:10.1063/1.98907

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Femtosecond transient absorption saturation measurements are used to investigate the scattering of optically excited carriers in AlGaAs. With pulses as short as 35 fs at 1.98 eV, scattering times ranging from 13 to 330 fs are observed in samples of AlxGa1−xAs withx=0, 0.1, 0.2, 0.3, and 0.4. A dramatic decrease in the rate of carrier scattering out of the initial optically excited states is observed with increasing Al concentration.

ISSN:0003-6951    

DOI:10.1063/1.98908

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We report an electro‐optically tunable, single‐frequency extended cavity laser with a linewidth of less than 60 kHz. The laser consists of a 1.5‐&mgr;m InGaAsP gain medium and an electro‐optically tunable, narrow‐band Ti:LiNbO3wavelength filter (&Dgr;&lgr;≊12 A˚). Electro‐optic tuning over at least 70 A˚ and single‐frequency operation with output power of more than 1 mW have been demonstrated. The laser linewidth was measured by beating the laser against a 1.523‐&mgr;m HeNe laser.

ISSN:0003-6951    

DOI:10.1063/1.98909

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Arsenic atoms sputtered from gallium arsenide wafers or arsenic‐dopedn‐type silicon wafers have been detected in argon plasmas using the laser‐induced fluorescence technique (LIF). Two methods of LIF detection were employed. One used a tunable, frequency‐doubled dye laser to pump a metastable transition of atomic arsenic at 228.81 nm. The second technique used the broadband output of an ArF excimer laser to pump a ground‐state transition of As at 193.76 nm.

ISSN:0003-6951    

DOI:10.1063/1.98910

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Low‐temperature transport measurements (down to 18 mK) are performed in CoSi2ultrathin films (down to 1.4 nm) epitaxially grown on silicon substrates. The low‐temperature residual resistivity exhibits little dependence on the CoSi2film thickness down to 10 nm. However, a steep increase is found below 10 nm, which is not taken into account by the Fuchs–Sondheimer [Proc. Cambridge Philos. Soc.34, 100 (1938)] boundary scattering theory. Correlatively, the superconducting critical temperature of these CoSi2films is abruptly depressed in the same thickness range. These two effects are phenomenologically explained by the presence of a perturbed layer, i.e., a CoSi2interfacial layer in which the electronic transport properties are dramatically diminished.

ISSN:0003-6951    

DOI:10.1063/1.98911

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Cross‐sectional transmission electron microscopy has been used to study the recrystallization behavior of a buried amorphous layer in 3 MeV Si+‐implanted (100) silicon at a dose of 5×1015cm−2. The lower (deeper) amorphous/crystalline (a/c) interface is found to be more abrupt compared to the upper (closer to the surface)a/cinterface. During recrystallization similar rates of advancement of the twoa/cinterfaces are observed.V‐shaped dislocations are observed in the completely recrystallized layer. The defect density in the upper recrystallized region is found to be higher than that in the lower recrystallized region. These observations are correlated with the shape of the damage profile. The secondary defects grown at higher temperatures (>750 °C) are found to be very stable and difficult to anneal out. The overall recrystallization behavior of the buried amorphous layer is found to be similar to that of lower energy implants.

ISSN:0003-6951    

DOI:10.1063/1.98912

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A theory of force constant models is derived for tetrahedral semiconductors from Harrison’s [Phys. Rev. B27, 3592 (1983)] tight‐binding theory. A relation between the three independent elastic constants is derived that is independent of the detailed form of the matrix elements. This relation provides an approximate, butabinitio, theory on which two‐parameter force constant models can be based. The universal matrix elements of Harrison are also found to describe remarkably well the magnitude of the elastic constants and their scaling from one material to another. Analytic forms forc11andc44are given in terms of the matrix elements.

ISSN:0003-6951    

DOI:10.1063/1.98913

出版商:AIP    

年代:1987

数据来源: AIP