摘要:

We have observed laser action at &lgr;=3.06 &mgr;m in In0.77Ga0.23As0.74Sb0.26/InP0.7Sb0.3double heterojunction, diode lasers, which were grown by organometallic vapor‐phase epitaxy. The maximum operating temperature wasT=35 K, and typical threshold current densities were 200–330 A/cm2. At temperatures up to 35 K, the lasing wavelength decreased with increasing temperature owing to a band‐filling effect.

ISSN:0003-6951    

DOI:10.1063/1.106101

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

O, N, or C impurity was separately incorporated intoa‐Si:H films by hot‐wall glow discharge decomposition. The effect of the impurity incorporation was investigated by electrical and electron spin resonance measurements. Both O and N impurities were found to increase the dark conductivity by decreasing its activation energy ina‐Si:H films. Furthermore, it was found that O and N impurities delay the photoresponse. C impurity, however, has no appreciable effect on them. These findings suggest that O and N impurities shift the Fermi level upward and form a trapping state for photoexcited electrons, supporting our O+3and N+4model.

ISSN:0003-6951    

DOI:10.1063/1.106102

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Deep level transient spectroscopy and double correlation technique were used to examine the annealing and profiles of interstitial iron in boron‐doped silicon at a temperature range from 50 to 400 °C. The results show that iron‐boron pairs begin to break‐up at a temperature as low as 50 °C. After a short time annealing (5 min) at a temperature up to 400 °C, most of the iron from the breaking is converted into interstitial iron. We also find that the distribution of interstitial iron under the silicon surface is not uniform, and it depends on the annealing time and temperature. The interstitial iron near the silicon surface decreases with the increase of the annealing time.

ISSN:0003-6951    

DOI:10.1063/1.106103

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A scanning tunneling microscope (STM) is used to locally modifyp‐njunctions on a scale of a few tens of nanometers. Thep‐njunction is composed of a phosphorus‐doped, hydrogenated amorphous Si [a‐Si:H(P)] layer deposited on heavily dopedp‐type crystalline Si(111). Under conditions of high current densities, with thep‐njunction biased in forward direction, thea‐Si:H layer is structurally changed leading to a decrease of the junction barrier height. The resulting exponential increase of hole injection into the modified amorphous layer leads to electronically active structures. They are detected by STM owing to their differing electronic properties.

ISSN:0003-6951    

DOI:10.1063/1.106104

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Photoluminescence of operational AlAs‐GaAs‐AlAs double‐barrier resonant tunneling structures withp‐type contact layers reveals the charging and subsequent discharging of the hole subbands in the quantum well by sequential resonant tunneling throughout the region of the first three hole resonances. The linewidth of the quantum well luminescence shows free‐carrier broadening at each of the resonances. Accumulation and tunneling of photocreated electrons are also prominent.

ISSN:0003-6951    

DOI:10.1063/1.106105

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A study of the absorption spectra of excitons in ZnSe‐ZnS strained layer superlattices (SLS) with well widths ranging from 0.6 to 7.6 nm is reported. Then=1 heavy hole (hh) and light hole (1h) exciton absorptions are clearly resolved for all samples even near room temperature. A theoretical estimation of then=1 hh exciton peak energy, which takes account of strain, quantum confinement of free carriers, and exciton binding energy enhancement by reduced dimensionality, is in excellent agreement with the experimental results. The variations in absorption linewidth and energy shift between absorption and emission band peaks, as a function of quantum well width, have also been measured: the experimental results provide evidence that the origin of the so‐called ‘‘Stokes’ shift’’ lies in Anderson localization due to monolayer fluctuations in the well width. The temperature dependence of the exciton peak energy and its linewidth are interpreted in terms of electron‐phonon and exciton‐phonon interactions.

ISSN:0003-6951    

DOI:10.1063/1.106106

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Using high dose implantation of Fe+into (111)Si, followed by rapid thermal annealing (RTA) at 1150 °C for 10 s, we fabricated continuous buried layers of the metallic &agr;‐FeSi2phase. Rutherford backscattering experiments indicate that these layers contain a large number of Fe vacancies, up to 18%. By implanting through a SiO2mask, we produced Schottky diodes with idealty factors of 1.4±0.1 and a Schottky barrier height of &Fgr;B=0.84±0.03 eV on (111)n‐Si. In this letter we report for the first time the formation of the semiconducting stoichiometric FeSi2(&bgr;‐FeSi2) phase by annealing the buried &agr;‐FeSi2layers below the phase transition temperature of 937 °C; specifically at 750 °C for 20 h.

ISSN:0003-6951    

DOI:10.1063/1.106107

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Atomic layer epitaxy (ALE) of GaAs is achieved in a relatively wide temperature range from 490 to 520 °C by using nitrogen carrier gas. For hydrogen carrier gas, the corresponding temperature range is only from 490 to 500 °C. The upper temperature limits for ALE correspond to the decomposition temperatures of TMG in each carrier gas. Gas analysis reveals that using nitrogen expands the temperature range by suppressing TMG decomposition.

ISSN:0003-6951    

DOI:10.1063/1.106108

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report a comparative analysis of photoluminescence and photoluminescence excitation of GaAs/AlGaAs quantum well structures grown by molecular beam epitaxy with and without growth interruption, which clearly indicates the improvement of interface quality when interruptions are used during growth. Time resolved spectroscopy, together with the temperature dependence of the integrated radiative recombination intensity, are used as a sensitive probe of the defect incorporation, which is usually observed to increase as a consequence of growth interruptions. We find that a significant increase of both extrinsic photoluminescence and nonradiative processes is not a necessary consequence of growth interruptions, unlike recent reports in the literature. We conclude that growth interruptions are compatible with the growth of high quality quantum well structures with a very high radiative efficiency.

ISSN:0003-6951    

DOI:10.1063/1.106109

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Selective plasma etching of Ge with a CF4/O2mixture is used to produce freestanding GaAs‐AlGaAs thin films. The etch rate of Ge substrates is as high as 150 &mgr;m/h at temperatures of 75 °C under optimized conditions and with a negligible etch rate for GaAs and AlGaAs materials. This plasma etching technique, combined with a lattice‐matched growth of GaAs‐AlGaAs structures on Ge substrates, has a variety of potential device applications. The characteristics of this etch process and the photoluminescence of freestanding AlGaAs‐GaAs structures are presented.

ISSN:0003-6951    

DOI:10.1063/1.106110

出版商:AIP    

年代:1991

数据来源: AIP