摘要:

A two step etching process has been used to fabricate wire and dot nanostructures from CdTe/CdZnTe quantum wells with high optical qualities. Wires and dots are first etched by the usual process of electron beam lithography and ion beam etching then, anodic oxidation is used to etch nanostructures to their final lateral sizes. We have observed remarkable improvements in the optical properties of these nanostructures as compared to the single step etching process. Their photoluminescence spectra are similar to that of the reference quantum well, with an exciton linewidth of about 3 meV, even for the smallest wires (100 nm) and dots (250 nm) which were studied. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113876

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Metal‐oxide‐semiconductor (MOS) capacitance–voltage (C–V) characteristics in the accumulation mode have been measured and simulated for polycrystalline Si gate MOS capacitors with various oxide thicknesses (40–200 A˚) onp‐type (100) Si substrates. The discrepancy between experimental data and theoretical prediction by classical MOS theories is clarified by taking quantization effects into account. The experimentally determined ‘‘effective dielectric thicknesses’’ in the semiconductors are found to be in good agreement with the values calculated from quantization effects for MOS capacitors with thinner oxides (<80 A˚). The effective dielectric thicknesses at oxide electric fields of 2–6 MV/cm have been determined to be 2–3 A˚ larger for the quantum mechanical case than for the classical case.

ISSN:0003-6951    

DOI:10.1063/1.113877

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Poole–Frenkel emission by transient current measurements in semi‐insulating polycrystalline silicon containing 35 at. % O has been investigated. In the presence of intense electric fields the conductivity of the material is strongly enhanced by the emission of free carriers. By applying square wave voltage signals, the field strength is modulated, thus producing current transients. By the analysis of these transients we have measured the emissivity of the traps responsible for the Poole–Frenkel effect as a function of temperature. The emissivity shows an activated behavior and the corresponding binding energy of the trap results equal to ≊0.64 eV. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113878

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Photoluminescence (PL) measurements were carried out on the porous Si layers kept in the HF solution. The PL peak around 700 nm, usually observed in the PL spectrum of the porous Si layer in the air, was no longer detected. This evidence suggests that the origin of the visible light luminescence from the porous Si layer in the air is different from that in the HF solution and may be associated with the presence of oxygen at the surface. Furthermore, it is interesting to find the cyclic shifts in the PL spectra between green and orange by turning the light on and off to illuminate the porous Si layer in the HF solution. This unique behavior is attributed to photochemical etching under illumination and chemical etching of the porous Si layer in the dark. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113879

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The release of hydrogen from Si1−xSnx:H (0≤x≤0.2) amorphous semiconductors prepared by reactive evaporation on substrates maintained at 77 K is monitored by effusion experiments. The effusion peaks are associated with desorption from voids. The deconvolution of these peaks allows one to deduce the different atomic configurations containing hydrogen and to determine their stability and their Gibbs free energy of desorption. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113880

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

An investigation of spectral hole burning effects is reported in the gain region of InGaAs/AlGaAs strained‐layer single quantum well diode lasers, using a heterodyne nondegenerate pump‐probe technique. This technique permits simultaneous measurement of the femtosecond dynamics and spectral dependence of transient gain in semiconductor lasers. At high bias current, strong spectral hole burning effects were observed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113881

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Structural and electrical properties of thermal SiO2layers on Si subjected to wafer bonding were studied. Regions with enhanced etching rate in HF‐solutions were found to appear after the bonding and a subsequent etchback of one of the wafers. The bonding procedure also leads to enhancement of interface state generation and accumulation of oxide trapped charge during injection of electrons or holes into the SiO2layer. The annealing behavior and capture cross section of these defects are close to those of centers generated when hydrogen is incorporated in the oxide network. Enrichment of the oxide by hydrogen during the bonding and postbonding anneal is suggested to be responsible for the degradation of the thermal oxide. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113882

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The influence ofinsituperturbations of the silicon target crystal electronic subsystem during H+ion implantation has been studied in terms of the type, density, and spatial distribution of accumulated deep traps. A perturbation of the electronic subsystem was achieved through application of a reverse bias to diode test structures. A substantial decrease in deep trap concentration is observed when ion implantation is accompanied by a superimposed reverse bias. The effect is especially pronounced for hydrogen related deep traps atEc−0.3. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113883

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The bound‐to‐continuum absorption inp‐type GaAs/AlGaAs quantum wells is calculated based on the electronic structure, wave functions, and optical matrix elements obtained from an 8×8 envelope‐function approximation (EFA) calculation without the use of an artificial large box to enclose the entire system; as such, the present work represents the first true continuum calculation. We show that, for an aluminum content of 30%, the well width of 48 A˚ (and not the 30 or 40 A˚ wells used previously) optimizes the linear absorption coefficient for bound‐to‐continuum absorption due to the presence of a resonant LH2 (second light‐hole) state at the top of the well. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113884

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Light emitting porous silicon thin films with thicknesses from ∼0.1 to ∼100 &mgr;m were produced by electrochemical etching and subsequently lifted off the silicon wafer by an electropolishing step. The structural integrity of the thinner layers was maintained by deposition on sapphire windows where they remain attached by van der Waals or electrostatic forces. The procedure for manufacturing high quality layers and their structural and optical properties is discussed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113885

出版商:AIP    

年代:1995

数据来源: AIP