摘要:

Although large changes in the absorption coefficient of multiple quantum wells (MQW’s) with applied voltage have been reported, no accurate measurement of the minimum absorption coefficient, which determines the absorption component of the device insertion loss, has been reported. Using a new measurement technique, we measure this minimum absorption coefficient, and determine that, for a device with a 10:1 on/off ratio and a 7 dB insertion loss, absorption contributes 2.2 dB of the insertion loss. We are able to predict absorption losses of future devices and show that, by a slight change in operating wavelength, the absorption loss can be greatly reduced.

ISSN:0003-6951    

DOI:10.1063/1.96924

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Two types of mesa‐type InGaAs/InPp‐i‐nphotodiodes have been fabricated from wafers grown by chemical beam epitaxy (CBE): (1) a conventional diffused InGaAs homojunction and (2) a novel InP/InGaAs/InP double heterojunction. Both types of devices have exhibited very low dark current, good quantum efficiency of 70% (without antireflection coatings), and transit‐time‐limited pulse response. The lowest dark currents, less than 1 nA at −10 V bias, have been achieved with the double heterojunction devices in spite of the fact that thep‐njunction is coincident with a heterojunction interface. This attests to the excellent quality of heterojunction interfaces grown by CBE. These results also unequivocally established that CBE is capable of producing high quality multilayer heterostructures for state‐of‐the‐art device applications.

ISSN:0003-6951    

DOI:10.1063/1.96925

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The fabrication and performance characteristics of 1.3 &mgr;m InGaAsP distributed feedback (DFB) lasers with multiquantum well (MQW) active layers are reported. The lasers are of the double channel planar buried heterostructure type and utilize a second order grating with a periodicity of ∼3900 A˚ for frequency selective feedback. The lasers have threshold currents in the range 25–35 mA at 30 °C and external differential quantum efficiencies of 0.2 mW/mA/facet at 30 °C. The temperature dependence of threshold current is characterized by aT0value of 95–100 K. The lasers have been operated to an output power of 19 mW in a single frequency. The measured dynamic linewidth under modulation is a factor of 2 smaller than that for regular double heterostructure lasers. The lower temperature dependence of threshold current and smaller dynamic linewidth make real index guided InGaAsP DFB MQW active layer lasers attractive for many system applications.

ISSN:0003-6951    

DOI:10.1063/1.96926

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Techniques are described by which an oriented zinc oxide film is sputtered directly on one side of an 80‐&mgr;m‐diam fused silica single‐mode optical fiber. A 4‐GHz piezoelectric transducer incorporating this film demonstrates that the film is oriented. Evidence of acoustic waves in the fiber is given by the swept‐frequency vector input impedance of the transducer. Acoustic transducers fabricated directly on a fiber produce fields focused on the fiber core for efficient acousto‐optic interactions, making possible many new fiber‐optic signal processing devices.

ISSN:0003-6951    

DOI:10.1063/1.96927

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Phase locked operation of an array of narrow diffused stripe conventional double heterostructure laser elements grown by metalorganic chemical vapor deposition is reported. Six‐element arrays (length 356 &mgr;m) show threshold currents of 33 mA per stripe and peak power outputs of at least 160 mW per facet with total external differential quantum efficiencies of 33%. Complex near‐field patterns are shown which result from two opposing mechanisms involved in guiding of the lateral modes. Three major lobes in far‐field patterns, which correspond to expected patterns for the lateral modes of gain guided arrays, are described.

ISSN:0003-6951    

DOI:10.1063/1.96928

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Damage introduced in silicon during reactive ion etching (RIE) in SF6gas mixtures has been studied using x‐ray photoelectron spectroscopy, Schottky barrier measurements, and Rutherford backscattering. RIE was done at 0.1 W cm−2power density with the rf cathode covered with a quartz plate, and the annealing behavior of damage was studied at various temperatures up to 800 °C in N2ambient. The results obtained indicate the following: (a) contamination by F, S, and metal ions is insignificant; (b) lighter atoms such as hydrogen cause higher electrical damage and lower lattice damage, both of which can be annealed at 400 °C; (c) heavier atoms such as argon cause lower electrical damage but higher lattice damage which requires a temperature ≥800 °C for recovery.

ISSN:0003-6951    

DOI:10.1063/1.96878

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Amorphous GeSe2films with Ag overlayers have been illuminatedinsituin a Rutherford backscattering chamber and the evolution of the silver depth profile as a function of illumination time has been studied. The silver distribution in the doped region is found to be steplike as had earlier been seen in the system Ag/As2S3and the composition of the photodoped product is approximately Ag1.1GexSe3−x. During the course of the reaction the silver/glass interface develops irregularities possibly due to the formation of silver islands.

ISSN:0003-6951    

DOI:10.1063/1.96879

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Rapid thermal annealing has been used to form Pd2Si by reacting thin layers of Pd metal on As‐implanted Si. An enhanced growth rate for the Pd2Si has been measured, which does not obey the diffusion limited growth kinetics as reported for the furnace reacted Pd2Si. The growing Pd2Si results in As redistribution which is sufficient to displace the shallowp‐njunction as the silicide/silicon interface approaches the junction position. The As‐implanted profile changes little in the Pd2Si region, with As accumulating at the leading edge of the silicide/silicon interface.

ISSN:0003-6951    

DOI:10.1063/1.96880

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The interdiffusion of nickel and zirconium by a solid‐state reaction to form an amorphous NiZr alloy has been followed by transmission electron microscopy. Cross‐sectional examination of NiZr bilayers annealed at 300 °C has shown the formation of amorphous NiZr and the development of large voids in the nickel neighboring the Ni/NiZr interface. Our results indicate that nickel is the dominant diffusing species in the amorphous alloy and that the diffusion requires a defect mechanism. Prolonged annealing at 300 °C results in the formation of a crystalline NiZr phase, which co‐exists with the amorphous alloy.

ISSN:0003-6951    

DOI:10.1063/1.96881

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We have measured the switching current transienti(t) versus time for 75‐nm‐thick KNO3nonvolatile memories having address voltages of 6.3 V and switching times 20–30 ns. The currents are minimum (nearly zero) att=0 and exhibit a symmetric shape about their maxima at 23±2 ns. This is compatible with Fatuzzo’s theory of sideways domain growth [Phys. Rev.127, 1999 (1962)] as well as with our earlier results on thickness dependence of coercive fieldEc∼d−1.3and field dependence of switching timests∼E−1.5. All of the results show that domain growth speed transverse to the applied field is the rate‐limiting parameter.

ISSN:0003-6951    

DOI:10.1063/1.96882

出版商:AIP    

年代:1986

数据来源: AIP