Abstract: Semiconductor compounds and a method for producing the same are provided wherein a method for growing at least one epitaxial layer of a II-VI semiconductor compound using MOVPE is used, the method including the steps of subjecting a substrate to organometallic and hydride precursor compounds in a MOVPE reactor at ultra low pressure, i.e. a pressure in the range of about 10 to 1 mTorr, whereby the organometallic and hydride precursor compounds react at a substrate surface without substantial reaction in the gas phase. The epitaxial layers and semiconductor compounds are useful in blue laser devices.

Abstract: Active acceptor concentrations of p-doped II-VI and III-V semiconductor compound layer provided by chemical vapor deposition are increased by photo-assisted annealing.

Abstract: The concentration of N acceptors in an as-grown epitaxial layer of a II-VI semiconductor compound is enhanced by the use of tertiary butyl amine as the dopant carrier, and is further enhanced by the use of photo-assisted growth using illumination whose wavelength is within the range of 200-250 nm.

Abstract: A method of providing an improved ohmic contact on an p-type ZnSe or ZnSSe layer provided on a substrate comprising immersing the layer in a Hg bath heated to a temperature in excess of 200.degree. C. for more than two hours.

Abstract: The concentration of N acceptors in an as-grown epitaxial layer of a II-VI semiconductor compound is enhanced by the use of tertiary butyl amine as the dopant carrier, and is further enhanced by the use of photo-assisted growth using illumination whose wavelength is at least above the bandgap energy of the compound at the growth temperature.

Abstract: A semiconductor structure with a p-type ZnSe layer has an improved ohmic contact consisting of a layer of Hg.sub.x Zn.sub.1-x Te.sub.a Se.sub.b Sc where x=0-1 with x being 0 at the surface of the ZnSe layer and increasing thereafter, a, b and c each =0-1 and a+b+c=1.

Abstract: An improved AC susceptometer and methodology for its use which is particularly suitable for the characterization of the properties of superconducting materials. Added to the circuitry of a conventional AC susceptometer is frequency domain analytical equipment for measuring the induced magnetic response. The addition of frequency domain measuring equipment permits the determination of the harmonic components of the induced magnetic response. The measurement of the harmonic components of the response also provides novel methodology for studying the phenomena of flux penetration, flux pinning and movement and permits the measurement of parameters such as lower critical field, critical temperatures, and the irreversibility line.

Abstract: An improved AC susceptometer and methodology for its use which is particularly suitable for the characterization of the properties of superconducting materials. Added to the circuitry of a conventional AC susceptometer is frequency domain analytical equipment for measuring the induced magnetic response. The addition of frequency domain measuring equipment permits the determination of the harmonic components of the induced magnetic response. The measurement of the harmonic components of the response also provides novel methodology for studying the phenomena of flux penetration, flux pinning and movement and permits the measurement of parameters such as lower critical field, critical temperatures, and the irreversibility line.

Abstract: Epitaxial layers of N-doped II-VI semiconductor compounds are grown on GaAs substrates by MOCVD using FME. Separating the growth and doping by alternating introduction of (1) the semiconductor cation and anion and (2) the cation and the dopant increases the level of doping, the level of activation, and the crystal quality.

Abstract: Apparatus and methodology for the rapid and inexpensive characterization of superconducting materials. The method and apparatus induces an alternating magnetic field in the sample to be tested. If the material is a superconductor odd harmonics are generated in the alternating magnetic response of the material near the transition temperature. The superconducting transitions are manifested by a peak or peaks in the odd harmonic components of the alternating magnetic response as a function of temperature. The peaks of the harmonic components are detected to indicate the presence and number of superconducting transitions.