Van der Pauw method

About: Van der Pauw method is a research topic. Over the lifetime, 1682 publications have been published within this topic receiving 25364 citations.

Strain-conserving doping of a pseudomorphic metastable Ge0.06Si0.94 layer on Si(100) by low-dose BF2+ implantation

Abstract: A thick (260 nm) pseudomorphic metastable n-type Ge0.06Si0.94 layer grown by molecular beam epitaxy on an n-type Si(100) substrate was implanted at room temperature with 70 keV BF2+ ions to a dose of 3×1013 cm−2, so that a p−n junction was formed in the GeSi layers. The samples were subsequently annealed for 10–40 s in a lamp furnace with a nitrogen ambient, or for 30 min in a vacuum-tube furnace. The samples were characterized by 2 MeV 4He backscattering/channeling spectrometry, double-crystal x-ray diffractometry, transmission electron microscopy, and by Hall effect measurements using the van der Pauw sample geometry. Samples annealed for either 40 s or 30 min at 800 °C exhibit full electrical activation of the boron in the GeSi epilayer without losing their strain. The Hall mobility of the holes is lower than that of p-type Si doped under the same experimental conditions. These results can be attributed to the Hall factor of heavily doped p-type GeSi films which is less than unity while the Hall factor...

Preparation and Study of the Structural, Optical and Electrical Properties of Cu(In,Ga)Se2 Thin Films

Abstract: Thin film samples of Cu(In,Ga)Se2 (CIGS) were prepared at room temperature by physical vapor deposition (PVD) technique using resistive heating method onto soda lime glass substrates. Deposition conditions were same for all the samples. The prepared samples were annealed in vacuum at temperature of 200 °C for 5, 10, 15, 30 and 60 minutes and were characterized structurally, optically and electrically. The structural analysis indicate the partial formation of quaternary CIGS compounds for the samples which were annealed in vacuum at 200 °C for 30 and 60 minutes. XRD analysis indicate that there is a continuous growth and improvement in the structural formation of ternary (CuInSe2 and CuGaSe2) and quaternary CIGS compounds. The thin films after vacuum annealing show low values of transmission and suitable absorption in the wavelength range of interest. The band gap of CIGS absorber layer is estimated to be 1.32 eV by extrapolating the plot of (a hu)2 as a function of hu. The electrical resistivity of all the samples are calculated by using Van der Pauw technique and found to decrease with increase in annealing time. The resistivity of the samples is small; therefore the prepared samples can be used as an absorber layer in the fabrication of thin film solar cells.

(110)-oriented indium tin oxide films grown on m- and r-plane sapphire substrates

Abstract: Indium tin oxide (ITO) thin films have been deposited by pulsed laser deposition on m-plane (100) and r-plane (012) sapphire substrates. For both substrates, the films were grown with their [110] direction perpendicular to the substrate planes under the conditions of high growth temperature and high oxygen pressure. Their in-plane epitaxial relations with the substrates were identified to be ITO[001] ∥ Al2O3[020] and for the m-plane substrate. For the r-plane substrate, two types of lattice matching were observed: one being and , the other being and . The electrical properties were measured by the Hall effect and van der Pauw methods at room temperature. All of the samples have low electrical resistivity on the order of 3.0 × 10−4 Ω cm, high carrier concentration of about 2.5 × 1020 cm−3, and mobility ranging from 70 to 90 cm2 V−1 s−1.

Elimination of slip lines in capless rapid thermal annealing of GaAs

Abstract: A new rapid thermal annealing (RTA) procedure has been developed that eliminates the problem of crystallographic slip in 2 in, ion-implanted GaAs wafers This annealing arrangement is easy to implement and is reliable A precision machined graphite support structure and guard ring are used to insure uniform cooling across the entire wafer, thus eliminating slip line production Characteristics of silicon ion implants have been determined using van der Pauw Hall, Polaron C–V profiling, and eddy current resistivity measurements Characterization showed excellent dopant activation and uniformity can be achieved using this new technique Low-temperature photoluminescence measurements were performed on samples annealed with and without graphite in the system, and no detectable difference in surface carbon contamination was found