摘要:

Stable, well‐defined conical structures have been observed to develop on the surface of excimer laser etched polyimide. Deliberate seeding shows that these are induced by the shielding effect of particulate impurities and indicates means for controlling the surface microstructure.

ISSN:0003-6951    

DOI:10.1063/1.97113

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The effects of conduction‐band nonparabolicity on quantized energy levels of an In0.5Ga0.5As /In0.5Al0.5As quantum well have been analyzed using the original Luttinger–Kohn ‘‘effective mass’’ equation, which is, in principle, valid as long as the perturbation to the periodic lattice potential can be regarded as slowly varying. The results differ substantially from those previously reported which employed the energy‐dependent effective mass approach.

ISSN:0003-6951    

DOI:10.1063/1.97114

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Cyclotron resonance of a two‐dimensional electron gas at a GaAs/GaAlAs interface is measured in the far infrared at intensities of up to 10 kW/cm2. Both the cyclotron mass and the carrier density are independent of intensity but the relaxation time changes with a dependence which is similar to that observed earlier in high dc field mobility studies.

ISSN:0003-6951    

DOI:10.1063/1.97115

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Ap‐channel field‐effect transistor with a 3.5 &mgr;m Cr/Au gate was fabricated from a modulation‐doped GaAs/In0.2Ga0.8As/GaAs quantum well structure. Well‐behaved transistor action was observed at both 300 and 77 K with extrinsic transconductances of 6.2 and 11.3 mS/mm, respectively. Shubnikov–deHaas measurements prove the existence of a two‐dimensional hole gas with a strain‐shifted light‐hole ground state associated with a light‐hole mass of 0.154m0.

ISSN:0003-6951    

DOI:10.1063/1.97116

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We report for the first time the successful use of the Hg1−xCdxTe native oxide as an encapsulation layer for an annealing process designed to activate an implanted impurity. The annealing process does not require Hg over pressure and consists of both furnace (∼200 °C) and rapid thermal (∼320 °C) anneals. Using 2.2 MeV4He+ion channeling measurements, we show that the implantation damage can be annealed out without loss of Hg from the substrate. Also, both secondary ion mass spectrometry and differential van der Pauw measurements indicate that the resulting electron concentration profile closely matches that of the implanted11B profile and the electrical junction is found to lie close to the expected position of the metallurgical junction.

ISSN:0003-6951    

DOI:10.1063/1.97117

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The epitaxial growth and properties of GaAs layers directly deposited on (100) Si substrates using a low‐temperature process are reported. The GaAs layers were grown by organometallic vapor phase epitaxy with a two‐step process and without any high‐temperature heat treatment of the Si substrates. The layers were of single domain with net carrier concentrations less than 1014cm−3. Intentionally dopedn‐type layers (Nd&bartil;1016cm−3) showed room‐temperature electron mobility of 5780 cm2/V s. The high structural quality of GaAs is demonstrated by device characteristics as well as by x‐ray diffraction measurements. The observation that an intrinsic mechanism dominates the photoluminescence spectra is another indication of high quality epitaxy.

ISSN:0003-6951    

DOI:10.1063/1.97118

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We have studied the effects of adding small amounts of In (0.2–1.2%) to GaAs grown by molecular beam epitaxy. The density of four electron traps decreases in concentration by an order of magnitude, and the peak intensities of prominent emissions in the excitonic spectra are reduced with increase in In content. Based on the higher surface migration rate of In, compared to Ga, at the growth temperatures it is apparent that the traps and the excitonic transitions are related to point defects. This agrees with earlier observations by F. Briones and D. M. Collins [J. Electron. Mater.11, 847 (1982)] and B. J. Skromme, S. S. Bose, B. Lee, T. S. Low, T. R. Lepkowski, R‐Y. DeJule, G. E. Stillman, and J. C. M. Hwang [J. Appl. Phys.58, 4702 (1985)].

ISSN:0003-6951    

DOI:10.1063/1.97119

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The possibility of achieving direct overwrite capability in magneto‐optic thin films is demonstrated. By using films having a compensation temperature tens of degrees higher than the ambient temperature, the demagnetizing field can effectively be used as a bias field for thermomagnetic writing in which writing and erasing of domains are accomplished in the absence of a magnetic field. A read‐before‐write scheme is proposed to facilitate the write/erase laser trigger signal to perform overwriting in real time.

ISSN:0003-6951    

DOI:10.1063/1.97120

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The first laser‐driven chemical reaction for etching ionic solids based on the fusion of salts in the molten phase is reported here for the reaction of LiNbO3with KF. The process involves spatially localized melting of LiNbO3by high‐power‐density laser pulses with photon energies in excess of the band gap of LiNbO3. While molten, LiNbO3undergoes reaction with KF to form niobium oxyfluoride anions by fusion of the salts. The resulting solid is highly water soluble. The insolubility of LiNbO3permits subsequent removal of only the irradiated area by rinsing in water. This laser‐driven chemical etching process shows great potential for applications which require either smooth surface morphology or very rapid etching rates.

ISSN:0003-6951    

DOI:10.1063/1.97121

出版商:AIP    

年代:1986

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.97123

出版商:AIP    

年代:1986

数据来源: AIP