摘要:

We have observed non‐ohmic conductivity inn‐type semi‐insulating GaAs. It has been accompanied by negative photoconductivity and giant magnetoresistance. Potential probe measurements show that the electric field increases from cathode to anode which indicates that electrons are injected at the cathode. Double injection is improbable on the basis of hole lifetimes and the absence of negative resistance regions. The threshold field for non‐ohmic behavior is weakly dependent on sample length. This implies either that the trapping parameters are strongly influenced by the electric field or that there is appreciable impact ionization of trapped, injected charge.

ISSN:0003-6951    

DOI:10.1063/1.1754790

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Measurements have been made of the shift in center frequency of the (2p4— 3s2) 6328‐Å20Ne transition in a Zee‐man discharge cell as a function of discharge current and gas filling. Such measurements are important for comparing the reproducibility and long‐term stability of laser stabilization systems which use the laser itself as a reference with those systems using an external discharge cell as a reference.

ISSN:0003-6951    

DOI:10.1063/1.1754791

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Measurements ofk*Cg, the complex dielectric constantk*times the geometrical capacityCg, of a metal‐oxide‐plasma capacitor have shown thatk*exhibits dispersion in the audio frequency range. A series of dielectric relaxation spectra has been obtained for Al2O3layers (anodized) by varying the plasma density. The dependence of the spectra on plasma density and oxide thickness is indicative of Maxwell‐Wagner behavior. A Cole‐Cole representation of the data shows a broadening of the dispersion toward low frequency with a secondary dispersion process appearing at low frequency. The main dispersion can be described by an empirical dispersion formula which represents an asymmetrical distribution of relaxation processes. The secondary dispersion may result from a very low frequency dispersion of the admittance components of the plasma sheath or from charge migration in the oxide.

ISSN:0003-6951    

DOI:10.1063/1.1754792

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Measurements of low‐impedance thin‐film tunneling junctions at room temperature frequently yield inaccurate values for the tunneling resistance. In some cases the indicated resistance is negative. A theory is developed which shows that the finite resistance of the metal films can account for the observations. Results, given for the resistance of a tunneling junction as a function of temperature, show good agreement between theory and experiment.

ISSN:0003-6951    

DOI:10.1063/1.1754793

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Complex changes in the distribution of thermally stimulated current peaks with illumination time and intensity are reported for a sample of semi‐insulating GaAs. With weak illumination for 5 sec, at least six peaks were seen, while after a 1‐min illumination only four peaks were evident. With stronger illumination, the thermally stimulated current essentially consisted of two major peaks, at about 115°K and 278°K. The 115° peak first increased with illumination time, passed through a maximum, and was quite small after a 12‐hr illumination, while the 278° peak became very large.

ISSN:0003-6951    

DOI:10.1063/1.1754795

出版商:AIP    

年代:1967

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.1754797

出版商:AIP    

年代:1967

数据来源: AIP