Andrew Preston

Boston University

The Future of Academic Research

  1. A Preston and
  2. D Johnston
, Dec 12 2011 The manner in which academic research is published has remained remarkably static relative to the upheaval currently underway in most other publishing industries. In this paper we examine the incentive structure ...

Photoconductivity in nanocrystalline GaN and amorhpous GaON

  1. A Koo,
  2. F Budde,
  3. A Bittar,
  4. A Preston,
  5. A Zeinert, et al.
in In this work we present a study of the optoelectronic properties of nanocrystalline GaN (nc-GaN) and amorphous GaON (a‐GaON) grown by ion-assisted deposition. The two classes of film show very distinct ...

Semiconducting ground state of GdN thin films

  1. S Granville,
  2. B Ruck,
  3. F Budde,
  4. A Koo,
  5. D Pringle, et al.
in We report the growth of GdN thin films and a study of their structure and magnetic and conducting properties. It is demonstrated that they are semiconducting at ambient temperature with nitrogen ...

Soft x-ray spectroscopic study of the ferromagnetic insulator V0.82Cr0.18O2

  1. L Piper,
  2. A DeMasi,
  3. S Cho,
  4. A Preston,
  5. J Laverock, et al.
in The chromium-vanadium oxide system V1−xCrxO2 (0.1<x<0.2) displays both insulating character in the rutile phase and room-temperature ferromagnetism. A combination of x-ray photoemission spectroscopy, resonant inelastic x-ray scattering, and resonant x-ray emission ...

Direct evidence of metallicity at ZnO (0001̅ )-(1×1) surfaces from angle-resolved photoemission spectroscopy

  1. L Piper ,
  2. A Preston ,
  3. S Cho ,
  4. A DeMasi and
  5. K Smith
in We have investigated the stability of O-polar ZnO (0001̅ )-(1×1) surfaces with photoemission spectroscopy and low-energy electron diffraction. We present direct evidence of quasi-two-dimensional electron gas (2DEG) formation (N2D≤2×1013 cm−2) at ...

Tunable electrical and optical properties of hafnium nitride thin films

  1. I Farrell,
  2. R Reeves,
  3. A Preston,
  4. B Ludbrook,
  5. J Downes, et al.
in We report structural and electronic properties of epitaxial hafnium nitride films grown on MgO by plasma-assisted pulsed laser deposition. The electronic structure measured using soft x-ray absorption and emission spectroscopy is ...

Electronic band structure information of GdN extracted from x-ray absorption and emission spectroscopy

  1. A Preston,
  2. B Ruck,
  3. W Lambrecht,
  4. L Piper,
  5. J Downes, et al.
in The electronic structure of GdN films grown by pulsed laser deposition has been investigated by soft x-ray absorption (XAS) and x-ray emission spectroscopy (XES) at the N K-edge. Density functional calculations ...

Electronic Structure of C60/Phthalocyanine/ITO Interfaces Studied using Soft X-ray Spectroscopies

  1. S Cho,
  2. L Piper,
  3. A DeMasi,
  4. A Preston,
  5. K Smith, et al.
in The interface electronic structure of a bilayer heterojunction of C60 and three different phthalocyanines grown on indium tin oxide (ITO) has been studied using synchrotron radiation-excited photoelectron spectroscopy. The energy difference ...

Growth and properties of epitaxial GdN

  1. B Ludbrook,
  2. I Farrell,
  3. M Kuebel,
  4. B Ruck,
  5. A Preston, et al.
in Epitaxial gadolinium nitride films with well-oriented crystallites of up to 30 nm have been grown on yttria-stabilized ziconia substrates using a plasma-assisted pulsed laser deposition technique. We observe that the epitaxial ...

Vibrational properties of rare-earth nitrides: Raman spectra and theory

  1. S Granville,
  2. C Meyer,
  3. A Preston,
  4. B Ludbrook,
  5. B Ruck, et al.
in Raman spectra are presented for the rare-earth nitrides SmN, GdN, DyN, ErN, and LuN measured with 633 and 514 nm excitation wavelengths and at temperatures above and below the Curie temperature. ...

Electronic properties of GaMnN thin films with high Mn content

  1. S Granville,
  2. B Ruck,
  3. A Preston,
  4. T Stewart,
  5. F Budde, et al.
in Optical and dc resistivity measurements as well as x-ray spectroscopies have been performed on (Ga,Mn)N films containing Mn at up to 11 at. %. The results indicate that at higher Mn ...

Near-zero moment ferromagnetism in the semiconductor SmN

  1. C Meyer,
  2. B Ruck,
  3. J Zhong,
  4. S Granville,
  5. A Preston, et al.
in The magnetic behavior of SmN has been investigated in stoichiometric polycrystalline films. All samples show ferromagnetic order with Curie temperature (TC) of 27±3 K, evidenced by the occurrence of hysteresis below ...

Band structure of ZnO from resonant x-ray emission spectroscopy

  1. A Preston,
  2. B Ruck,
  3. L Piper,
  4. A DeMasi,
  5. K Smith, et al.
in Soft x-ray emission and absorption spectroscopy of the O K-edge are employed to investigate the electronic structure of wurtzite ZnO(0001). A quasiparticle band structure calculated within the GW approximation agrees well ...

Comparison between experiment and calculated band structures for DyN and SmN

  1. A Preston,
  2. S Granville,
  3. D Housden,
  4. B Ludbrook,
  5. B Ruck, et al.
in We investigate the electronic band structure of two of the rare-earth nitrides, DyN and SmN. Resistivity measurements imply that both materials have a semiconducting ground state, and both show resistivity anomalies ...

Ferromagnetic redshift of the optical gap in GdN

  1. H Trodahl,
  2. A Preston,
  3. J Zhong,
  4. B Ruck,
  5. N Strickland, et al.
in We report measurements of the optical gap in a GdN film at temperatures from 300 to 6 K, covering both the paramagnetic and ferromagnetic phases. The gap is 1.31 eV in ...

Electronic structure of the rare-earth nitrides

  1. A Preston
, Feb 27 2011 The rare-earth nitrides (ReNs) are a class of novel materials with potential for use in spintronics applications. Theoretical studies indicate that among the ReNs there could be half-metals, semimetals and semiconductors, ...

Photocurrent diffusion length in disordered GaN

  1. A Koo,
  2. F Budde,
  3. B Ruck,
  4. H Trodahl,
  5. A Bittar, et al.
in The diffusion length of carriers in semiconductors is a significant parameter determining the suitability of a material for device applications. Here we describe a simple new technique to measure diffusion length ...

No public reviews to display.

No comments to display.

Active user

Sign up to create your own profile or send a message.

Metrics

  • Date joined Feb 19 2011
  • Known publications 17
  • Reviews 0
  • Comments 0

Affiliations