The band structure and band alignment for ScxAl1-xN /AlN heterojunctions, with Sc-content x up to 25%, are investigated via first principle density functional theory (DFT) calculations. The supercell approach is utilized to build the crystal structure of ScAlN and AlN alloys and we investigate the natural band offsets of ScxAl1-xN relative to AlN through the potential line-up method. Our calculations suggest a type-I ScAlN / GaN heterostructure with large band offsets. The implementation of ScAlN will have impacts for deep ultraviolet, power electronics, and laser devices.
Efficient p-type doping of III-nitride materials is notoriously difficult due to their large band gaps, intrinsic n-type doping, and the large ionization energy of acceptors. Dilute-anion III-nitride materials are a promising solution for addressing this issue and increasing the activation efficiency of p-type dopants. Upward movement of the valence bands reduces the ionization energy of the dopants, allowing for enhanced p-type conductivity in comparison to the conventional nitrides. Incorporation of a dilute-arsenic impurity into AlN significantly reduces the ionization energy of Mg-acceptors from 500 meV to 286 meV, allowing for a two-order magnitude increase in activation efficiency in 6.25%-As AlNAs.
The material gain and threshold current density properties of dilute-As InGaNAs-based quantum wells (QWs) are analyzed via a self-consistent 6-band k·p formulism. Amber emission is achieved by the implementation of dilute-As InGaNAs with low In-content. Significant threshold current density reduction and enhanced material gain are obtained by the employment of an In0.19Ga0.81N0.97As0.03 (Eg ~ 2.1 eV) alloy into the active region for red-emitting lasers, compared to a conventional high In-content InGaN-based QW emitting at the same wavelength (λ~600 nm). Our study reveals the excellent potential of the dilute-As InGaNAs for implementation as the active region for red-emitting lasers.
Magnesium oxide (MgO) is a promising dielectric for use with GaN due its similar crystal structure and lattice constant, large bandgap, and high dielectric constant. We report on the structural properties of MgO films deposited on GaN templates on sapphire substrates via the atomic layer deposition (ALD) technique. Analysis of the crystal quality and structure as a function of surface treatment and growth temperature are presented. I-V and C-V measurements of MgO/GaN metal-oxide-semiconductor capacitance structures are also presented.
Experimental measurements of optical and crystallinity properties of MOCVD-grown quaternary AlGaInN lattice-matched to GaN are presented. The bandgaps, carrier life times, optical constants (n vs. k), doping profiles, effective masses, and structural and surface information from XRD and AFM are presented. This study reports important material parameters for the alloy, which will be key in the design and application of these alloys for UV and visible spectral regime optoelectronic devices.
The self-consistent 6-band k∙p calculations of AlGaInN barriers surrounding the InGaN quantum well (QW) emitting at ~495 nm show ~ 30% increase in material gain and ~ 40% reduction in threshold current density, compared to the conventional InGaN / GaN QW structure. Following the guidance of our computational study, the InGaN / AlGaInN multiple QW structures with different AlGaInN alloy compositions lattice-matched to GaN are grown via MOVPE. The use of InGaN / AlInN QW structure resulted in improved luminescence, and the results of InGaN / AlGaInN with larger compositional range will also be presented.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.