摘要:

Homogeneous injection of holes into the gate oxide of metal‐oxide‐semiconductor (MOS) devices was obtained usingp‐channel MOS transistors under illumination conditions. Because gate hole currents could be measured the dependence of the hole trapping on the oxide electric field and on the energy of the holes at the injection point could be investigated. In contrast to results recently reported for electron injection no evidence for the generation of traps during hole injection was found. Only a small dependence of the capture cross section on the oxide field was observed. The study of the interface state generation during hole injection at various fields revealed that the amount of interface states directly generated by the injected holes is less than 5% of the number of trapped holes. For longer times a transformation process occurs and a correlation is found between the detrapping of holes and the generation of interface states.

ISSN:0021-8979    

DOI:10.1063/1.345827

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The relaxation‐time approximation is used in the numerical simulation of the Wigner distribution function to incorporate scattering. The effects within the constant relaxation‐time approximation are (a) a decrease in the peak‐to‐valley ratio of the current‐voltage curve; (b) a reduction in the oscillations of the Wigner distribution function, especially at resonance bias; (c) a suppression of the decay time of current oscillations after a sudden bias shift, indicating a smaller switching time than for no scattering; (d) a degradation in the resonant tunneling trajectories towards the characteristics of nonresonant trajectories; (e) a decrease in the spatial range of the quantum influences near resonance; and (f) ballistic transport sets in [i.e., the mean free path of the electrons is greater than the barrier region (110 A˚)] for temperatures less than 74 K.

ISSN:0021-8979    

DOI:10.1063/1.345828

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

GaAs quantum well infrared detectors with peak responsivity at 8.2 &mgr;m and significant response beyond 10 &mgr;m have been demonstrated with detectivities of 4×1011cm (Hz)1/2/W at 6 K; this detectivity is the highest reported for a quantum well detector. The detectors comprised 50 GaAs quantum wells of width 40 A˚ with an average Si doping density of 1×1018cm−3separated by 280‐A˚ barriers of Al0.28Ga0.72As. In this design, the state to which electrons are excited by infrared absorption and from which they are subsequently collected lies in the continuum above the energy of the Al0.28Ga0.72As conduction‐band minimum. The maximum detector responsivity was mesured to be 0.34 A/W. The device dark current density is 5.5×10−6A/cm2with the detector biased for maximum detectivity (3.5 V), and the dark current remains constant with increasing temperature up to 50 K. The detector noise current was observed to be a constant fraction (70%) of the shot noise down to noise currents of 10−14A/(Hz)1/2. A theoretical model for the dark conduction process in a quantum well detector has been developed which successfully predicts the observed dark current noise.

ISSN:0021-8979    

DOI:10.1063/1.345829

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We explore the effect of forming gas anneals at 110 °C onE’centers in metal/oxide/semiconductor oxides subjected to gamma, electron, and vacuum ultraviolet irradiation, as well as high electric field stressing. We find that this brief low‐temperature anneal substantially reducesE’density in all cases, clearly demonstrating that hydrogen reacts readily with theE’sites. Although this work confirms a recent report of the reactivity ofE’and hydrogen we fail to detect the reported reaction product known as the 74‐G doublet.

ISSN:0021-8979    

DOI:10.1063/1.345830

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Active mode‐locking of a laser diode in an external cavity has led to the observation of new instabilities. We report period‐doubling manifested by the alternation of weak and strong pulses in the mode‐locked laser pulse train. We also report period‐quadrupling where four successive pulses have different amplitudes. These results are attributed to the imperfect antireflection coating of the semiconductor chip, the latter constituting a regenerative amplifier with a time‐dependent delay for amplification. A qualitative analysis is proposed and validated by numerical simulations from a diode laser rate equation model.

ISSN:0021-8979    

DOI:10.1063/1.345802

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Recent results suggesting that 78‐meV acceptors appear only inn‐type material while 68‐meV acceptors appear inp‐type material are in direct conflict with several clear experiments which establish the existence of a 78‐meV acceptor inp‐type GaAs beyond any reasonable doubt. The available evidence for the 78‐meV center is reviewed and some possible sources of error in DLTS and photoluminescence data are mentioned.

ISSN:0021-8979    

DOI:10.1063/1.345803

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Considering all aspects of the comment and the most recent deep level transient spectroscopy (DLTS) and Raman scattering results, we conclude that the 68‐meV single aceptor center does exist in Ga‐rich,p‐type GaAs at concentrations exceeding that of the 78‐meV center. Discussion in the comment which misconstrues our results is pointed out and a rebuttal is given to the unfounded objections against DLTS data.

ISSN:0021-8979    

DOI:10.1063/1.346102

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Results from a cyclotron autoresonance maser experiment are reported. Two maxima of the output microwave power (8 and 10 MW) at a wavelength of 5 and 5.5 mm, respectively, have been observed. The nonadiabatic beam pumping is achieved by transit of the electrons through an external magnetic‐field local inhomogeneity due to the presence of a copper aperture.

ISSN:0021-8979    

DOI:10.1063/1.345804

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

It has been shown that the variation of energy flux of a transient electromagnetic field with distances, under some conditions, may obey a slowly decaying way instead of the usual inverse‐square law. In this communication we present that the pulse beams whose spectra are depicted with the Gaussian beam theory may have slowly decreasing energy flux in the paraxial region. This result contributes new signficance to both the slowly decaying wave theory and the Gaussian beam theory.

ISSN:0021-8979    

DOI:10.1063/1.345805

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A relatively simple experimental method to estimate a diffusivity of silicon interstitials is described. In the low‐temperature range between 460 and 500 °C, oxygen thermal donors are used as a monitor for silicon interstitials. The estimated diffusivity of silicon interstitials at oxygen‐donor‐formation temperatures is fitted to previously‐published results from oxidation‐enhanced and retarded‐diffusion experiments at temperatures above 950 °C. In the temperature range between 460 and 1200 °C, the diffusivity of silicon interstitials is described by the Arrhenius equation,Di=3.35×10−1 exp(−1.86/kT) cm2/s.

ISSN:0021-8979    

DOI:10.1063/1.345806

出版商:AIP    

年代:1990

数据来源: AIP