摘要:

The diffusion coefficient of oxygen in heavily antimony doped Czochralski Si was measured in the temperature range 950–1100 °C by using secondary ion mass spectroscopy (SIMS). The diffusion coefficient, obtained from SIMS oxygen concentration profiles in samples submitted to out diffusion, shows no dependence on antimony concentration. The combined data give an activation energy of 2.68 eV, which is in good agreement with published results.

ISSN:0021-8979    

DOI:10.1063/1.346311

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Very short far‐infrared (FIR) pulses have been generated by cavity dumping an optically pumped molecular gas laser using optical switching techniques. The active element used is an intracavity semiconductor, which is placed under the Brewster angle with respect to the optical axes. This element is made highly reflective by the sudden increase of the free‐carrier concentration, induced by above band‐gap illumination. In this way high power (∝1 kW) FIR pulses with a duration less than 10 ns can be produced.

ISSN:0021-8979    

DOI:10.1063/1.347167

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Several papers devoted to the Stark widths ofns‐nptransitions of the homologous sequence Neii, Arii, Kriiand Xeiiwere published (n=n0+1, wheren0is the principal quantum number of the ground level). From their analysis, a general trend for this sequence is established in function of two relevant atomic parameters for the description of Stark line widths: the atomic number,Zand the upper level ionization potential. The experiments of Viteletal. shows that, due to a dense plasma effect, a nonlinear dependence between the Stark parameters and the electron density exists:w∝N&ggr;e. From the general trend, the value &ggr;=5/6 is established.

ISSN:0021-8979    

DOI:10.1063/1.346286

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

In a methane/argon discharge used for deposition of hydrogenated amorphous carbon (a‐C@B:H), energetic ion bombardment yields radicals on solid surfaces by two mechanisms: (i)fragmentation of hydrocarbon ions at their impact on the surface and (ii)sputtering of the already depositeda‐C:H film. To discriminate between these two mechanisms, the emission intensity of CH(A‐X) in the vicinity of a negatively biased electrode was measured as a function of the ion impact energy. The threshold energy for yielding the excited CH radical was found to be ∼2 eV for fragmentation and ∼80 eV for sputtering. The fragmentation yield is much larger on a metal surface than ona‐C:H layer. The sputtering yield dominates over the fragmentation yield for the high impact energy(>150 eV).

ISSN:0021-8979    

DOI:10.1063/1.346287

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The light‐induced decrease of the photoconductivity in deuterated amorphous silicon is a factor of 3 less even though the defect density increase is greater than in hydrogenated material having equivalent as‐deposited properties. Consequent changes in the average recombination cross section of the defects is illustrated. Since the differences in the light soaking behavior upon isotopic substitution has been found to disappear in films deposited at low temperatures, the changes are thought to arise from differences in the silicon network occurring during growth.

ISSN:0021-8979    

DOI:10.1063/1.346288

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Absorption ofp‐type GaAs crystals grown by horizontal Bridgman, liquid‐encapsulated Czochralski, and liquid‐phase electroepitaxy methods were measured at 4 K. The spectra of melt‐grown crystals show a wide absorption band extending from 0.6 eV to the fundamental absorption edge. The comparison with the photocapacitance spectrum of EL2 defect and deep‐level transient spectroscopy measurements allowed to interpret this absorption as due to transitions between the valence band and the doubly ionized EL2 level. Absorption can be bleached by intense illumination at temperatures below 60 K with the dark spectrum recovering upon heating with an activation energy of 55 meV.

ISSN:0021-8979    

DOI:10.1063/1.346289

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The current‐voltage (I‐V) behavior of a GaSb(p)/AlSb/InAs/AlSb/GaSb(p) resonant interband tunneling (RIT) heterostructure is analyzed experimentally and theoretically. The structure has been successfully grown on a (100)‐oriented GaAs substrate by molecular‐beam epitaxy, demonstrating that more exotic lattice‐matched substrates (such as InAs or GaSb) are not required for RIT devices. Theoretical simulations ofI‐Vbehavior are developed, employing a two‐band tight‐binding model. ExperimentalI‐Vcurves show pronounced negative differential resistance, with a peak‐to‐valley current ratio of 8.3 at 300 K. Good agreement is observed between measured and calculated peak current densities, consistent with light‐hole tunneling through the confined InAs conduction‐band state.

ISSN:0021-8979    

DOI:10.1063/1.346290

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A predictive model for band‐gap narrowing has been applied to several III‐V semiconductors. Band‐gap narrowing is expressed as &Dgr;Eg=AN1/3+BN1/4+CN1/2; values forA,B, andCare predicted for these materials. The commonly usedN1/3relation is shown to be valid for thep‐type materials considered, but not forn‐type materials.

ISSN:0021-8979    

DOI:10.1063/1.346291

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Epitaxial growth of GaAs has been performed with diethylarsine (DEAs) to investigate its potential as a replacement of arsine. Triethylgallium (TEG) and trimethylgallium (TMG) were used as group‐III sources and carbon incorporation into the epilayers was compared. The growths were carried out under low‐pressure conditions (130 Pa–1.3 kPa) to avoid a gas‐phase reaction between the precursors. All epilayers exhibitedp‐type conductivity,and the main acceptor impurity was carbon. The lowest hole concentrations were ∼1016and ∼1017cm−3for TEG and TMG, respectively. The dependence of hole concentration on V/III ratio suggests that the carbon incorporation comes mainly from TMG and DEAs for the TMG/DEAs mixture, and from DEAs for the TEG/DEAs mixture. These results indicated that the contribution of the H atom from the As—H bond in DEAs on reduction of carbon incorporation was not enough to grow high‐purity GaAs.

ISSN:0021-8979    

DOI:10.1063/1.346292

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Coupling interactions between the low loss‐modes of dielectric waveguides and the high‐loss modes supported by semiconductor waveguide claddings are of prime importance in the design and fabrication of integrated optical photodetectors and polarizers. It is desirable to maximize energy transfer from dielectric waveguides to semiconductor claddings in order to achieve optimal operation of detectors and polarizers. We have experimentally verified that the intermodal coupling of light from a low‐loss dielectric guiding region to a highly absorbing semiconductor cladding region is periodic as a function of cladding thickness. Results were obtained by theinsitumonitoring of output intensity during the growth and etching of hydrogenated amorphous silicon on polarization‐preserving, D‐shaped, optical fiber. Strong correlation exists between theoretical and experimental results for both TE and TM polarizations. Theinsitu, intensity monitoring technique allows for precise control of attenuation characteristics in clad‐waveguide devices allowing for optimum performance of clad‐waveguide polarizers and detectors.

ISSN:0021-8979    

DOI:10.1063/1.346293

出版商:AIP    

年代:1990

数据来源: AIP