摘要:

The magnitudes of the nonlinear optical susceptibilities of trigonal selenium, cadmium telluride, and indium antimonide have been measured at 28.0 &mgr;m relative to d11(tellurium). By comparison to the recently measured absolute value for tellurium, d11(Te)=(5.7±1.6×10−10m/V, the values obtained in this work are d11(Se)=(18.4±8.6)×10−10m/V, d14(CdTe)=(5.9±2.4)×10−11m/V, and d14(InSb)=(5.6±2.3)×10−10m/V. For Te, CdTe, and InSb, the measured 28.0 &mgr;m value is less than the 10.6 &mgr;m value, while for Se, the 28.0 &mgr;m value is considerably larger than the 10.6 value. These seemingly inconsistent results are explained using Garrett's anharmonic oscillator model.

ISSN:0021-8979    

DOI:10.1063/1.1661868

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The deflection of optical guided waves by acoustic waves in layered media is studied. The electric fields that arise in this scattering process lead to complex radiated power distributions. In particular, it is shown that field effects can influence coupling efficiency and beamwidth and that these effects must be included in any description of acoustic‐optic light deflection from optical waveguides.

ISSN:0021-8979    

DOI:10.1063/1.1661869

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The longitudinal electro‐optic effect in ferroelectric tetragonal barium strontium niobate has been investigated in thin 45° plates of compositionx= 0.3. The half‐wave voltage for the linear electro‐optic effect at room temperature is approximately 1 kV. The half‐wave voltage decreases as the temperature approaches the transition and reaches a minimum value of about 100 V at 55 °C. The linear effect is observed to become quadratic near the transition and to remain quadratic up to the limit of observation (90 °C). Around the transition temperature the quadratic effect has a low half‐wave voltage, and is a slowly varying function of temperature. The high half‐wave voltage for the room‐temperature linear electro‐optic effect is attributed to the occurrence of a strongly nonlinear polarization characteristic. The quadratic effect is thought to occur when the material is in a depoled ferroelectric state or in a degenerate4¯2mphase.

ISSN:0021-8979    

DOI:10.1063/1.1661871

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The dynamic loss of a cw dye laser was determined by measuring input‐output curves at a fixed wavelength for a variety of wavelengths. The actual losses were obtained from the constants of the straight‐line fits for plots of threshold power vs the negative logarithm of the output reflectivity and the inverse slope efficiency vs the inverse of the output mirror transmission. A simplified kinetic‐dynamic model of the cw dye laser has been developed to interpret the experimental data. The model is consistent with experiment in the interpretation of the loss information and, with the use of reasonable molecular constants, is also consistent with the dependence of threshold power on the output reflectivity. The actual loss measured is different, at the shorter wavelengths of oscillation, for the two approaches. This difference arises because the population‐dependent losses (singlet and triplet absorption of the intracavity laser flux) contribute differently to the efficiency and the threshold. At the longer wavelengths (> 6000 Å) of oscillation these contributions to the loss become very small and the residual scattering, reflection, and diffraction losses remain. The simplified model is successful in dealing with the loss and threshold data and a measure of the triplet‐triplet absorption constant can be obtained by combining the kinetic analysis and fitting the threshold power data. The model is less successful in the area of efficiency and this appears to be related to some of the approximations used. A single numerical correction factor, however, brings the efficiency data into reasonable agreement with the model.

ISSN:0021-8979    

DOI:10.1063/1.1661872

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

When As diffuses into Si, only a fraction of the As remains electrically active. Because of the importance of As as an emitter dopant, it is necessary to understand the nature of the inactive As and how it affects the solubility and diffusion of As+ions. A model is proposed in which As+diffuses via a simple vacancy mechanism while in quasiequilibrium with [VSiAs2] complexes. The flux of mobile monatomic As+is modified according to the extent of [VSiAs2] complex formation. The structure of this defect and its formation energy (≈ 1.8 eV) are discussed. An effective diffusion coefficient is derived using this model:DAs=2DiCA /(1+8 K2′ CA3)whereCAis the As+concentration andK2′is a collective parameter that depends upon As+surface concentration and the diffusion temperature. Experimental verification of the correctness of this equation is given. The important results of this quantitative analysis show thatDAsreaches a maximum value with increasing As concentration, and then decreases monotonically. The As concentration at whichDmaxoccurs is dependent upon the total As surface doping and the diffusion temperature. The ratio of total As to electrically active As+decreases to a value of unity at 1300 °C. At 1250 °C it is shown that the solubility of As+reaches a maximum value of 1.5 × 1021atoms/cm3inp‐type Si and 1.2 × 1021atoms/cm3inn‐type Si.

ISSN:0021-8979    

DOI:10.1063/1.1661873

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

It has been observed that considerable discrepancy occurs between total As in Si diffusion profiles obtained by Irvin's curve and those determined by neutron‐activation analysis. This discripancy can be explained in terms of the formation of inactive [VSiAs2] complexes. Under conditions of equilibrium between As+ions and [VSiAs2] complexes, it is possible to derive the relation‐relationship between total As,CT, and bulk resistivity, &rgr;, by using Irvin's curve as a standard. It is shown that a singleCT‐vs‐&rgr; curve is not sufficient because of the temperature and initial Si substrate dopant dependence of [VSiAs2] complex formation. Equilibrated near‐Si‐surface As data obtained by activation analysis and resistivity measurements are presented to verify the theory. Excellent agreement is obtained. The important result of this study is that it is now possible to determinepartiallythe AsCT(x) diffusion profile from four‐point probe measurements and anodic sectioning of the Si. While this technique can only be used over approximately the first 50% of the diffused layer, the rest of theCT(x) profile can be estimated from the electrically active As profile,CA(x) (determined by Irvin's curve) and an equation relatingCT(x) toCA(x).

ISSN:0021-8979    

DOI:10.1063/1.1661874

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

When As is sequentially diffused into Ga or B‐doped Si, a retardation of thep‐type base layer is generally observed. This is in contrast to the ``emitter‐push'' effect associated with sequential phosphorus diffusions. In order to simulate transistor profiles it is necessary to be able to quantitatively describe the emmiter‐base interactions during diffusion. In this study, the way in which the internal electric field, the equilibrium vacancy density, ion pairing, and the rate of [VSiAS2] complex formation affect the redistribution of the base layer during sequential processing was investigated. Numerical solutions to coupled diffusion equations indicate that the electric field and ion‐pairing effects only cause localized retardation of a B profile during the As emitter diffusion. However, the formation of [VSiAs2] complexes causes a vacancy undersaturation in the Si to a distance in the crystal well beyond most practical collector‐base junction depths. Since the local‐base diffusivity depends upon the vacancy density, this extrinsic vacancy undersaturation effect causes the expected retarded base diffusion. Experimental verification of the correctness of the theory present is given as a function of emitter‐ and base‐surface concentrations, initial base depths, and times and temperatures.

ISSN:0021-8979    

DOI:10.1063/1.1661875

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Single‐crystal layers of AlN have been grown on sapphire substrates between 1000 and 1100 °C by vapor‐phase reaction of aluminum chlorides with ammonia. The purity, color, crystallinity, growth morphology, and electrical resistivity of the epitaxial layers have been investigated. Infrared specular reflection measurements showed the presence of an appreciable strain at the AlN‐sapphire epitaxy interface. Optical absorption data strongly suggest the AlN is adirectband‐gap material with a value of about 6.2 eV at room temperature.

ISSN:0021-8979    

DOI:10.1063/1.1661876

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The classical experiment of the microwave transmission through an axially magnetized semiconductor sample filling a waveguide is analyzed in terms of modal analysis, with a direct use of the guided helicon modes and of their adjoint modes. The validity of the numerical results is established by directly checking the continuity of the transverse components of the electromagnetic field through the vacuum semiconductor junctions. The calculation predicts satellite dimensional resonances, due to the higher helicon modes. These satellite resonances disappear if sufficient inhomogeneities, i.e., carrier density fluctuation of about 10%, are introduced in the mathematical model of the sample.

ISSN:0021-8979    

DOI:10.1063/1.1661877

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A new three‐electrode glass switch device is described that shows performance like a thyrister. The planar electrodes are obtained by dividing a chromium layer by two perpendicular gaps in four parts. Two of these parts are connected and form the common electrode. The two remaining parts are used as control electrode and load electrode. The device is in the on state, if the load electrode is connected by a conducting filament to the common electrode. Investigations of the performance of the new device show that the load diode can be triggered by a voltage pulse supplied to the control electrode if the control diode is in the off state. It can also be triggered by a current pulse supplied to the control electrode, if the control diode is in the on state and operated by a dc current. The measured performance of the new device is explained under the assumption that in both diodes a thermal‐switching mechanism takes place.

ISSN:0021-8979    

DOI:10.1063/1.1661878

出版商:AIP    

年代:1973

数据来源: AIP