Growth and Electronic Properties of InN and N-rich Alloys
Lead Research Organisation:
University of Warwick
Department Name: Physics
Abstract
This project will study the growth and characterisation of a new optoelectronic semiconductor material, namely indium nitride (InN). Starting from the deposition of the first few atoms that make up a single atomic layer of the material, the growth will be observed using scanning tunnelling microscopy (STM), through to the development of complete monolayers, and all the way to the growth of thin films (i.e. several microns thick). This material is important technologically because up until late 2002, it was thought that InN had a band-gap energy of 1.9 eV. However, in 2002, high quality InN thin films were grown for the first time and this material was found to have a band-gap energy of 0.7 eV (i.e. in the infra-red). This discovery has meant that it is important to re-assess all of the fundamental properties (i.e. structural, optical and electronic properties) of this material and its alloys. The technologically important reason for this is that now, with this lower band-gap energy, InN can be combined with the wide-gap material GaN (band gap of 3.4 eV / i.e. in the ultra-violet) to form InGaN. It will therefore be possible to make a whole range of new devices, including a range of high efficiency solar cells spanning the entire solar spectrum, and high frequency devices that operate in the THz band, without having to combine several different semiconductor materials, with all the problems that go with that complex process. Because of a range of inherent properties associated with pure InN (surface electron accumulation and difficulty with p-type doping) which we have previously discovered, we will develop a range of novel alloys of this material with both gallium (Ga) and arsenic (As). We will do this by carefully examining how these materials grow (quite literally atomic layer-by-atomic layer) and what fundamental properties of the thin films improve, as a function of Ga and As content, enabling a whole range of new optical and electronic device applications.
Publications
King P
(2008)
Valence band density of states of zinc-blende and wurtzite InN from x-ray photoemission spectroscopy and first-principles calculations
in Physical Review B
King P
(2008)
The influence of conduction band plasmons on core-level photoemission spectra of InN
in Surface Science
King P
(2008)
InN/GaN valence band offset: High-resolution x-ray photoemission spectroscopy measurements
in Physical Review B
King P
(2008)
Surface electronic properties of undoped InAlN alloys
in Applied Physics Letters
King P
(2008)
Surface electronic properties of n- and p-type InGaN alloys
in physica status solidi (b)
King P
(2008)
Determination of the branch-point energy of InN: Chemical trends in common-cation and common-anion semiconductors
in Physical Review B
King P
(2008)
Influence of growth conditions and polarity on interface-related electron density in InN
in Journal of Applied Physics
Bailey L
(2008)
Band bending at the surfaces of In-rich InGaN alloys
in Journal of Applied Physics
Piper L
(2008)
Observation of quantized subband states and evidence for surface electron accumulation in CdO from angle-resolved photoemission spectroscopy
in Physical Review B
Description | Boston University |
Organisation | Boston University |
Country | United States |
Sector | Academic/University |
Start Year | 2007 |
Description | Sharp Laboratories of Europe Ltd |
Organisation | Sharp Laboratories of Europe Ltd |
Country | United Kingdom |
Sector | Private |
Start Year | 2007 |