Electrical and optical properties of iron in GaN, AlN, and InN

Abstract

Iron is a common trace impurity in the group-III nitrides. Iron is also intentionally introduced in III-nitride electronic devices to create semi-insulating substrates and in the context of spintronics and quantum information applications. Despite the wide-ranging consequences of iron's presence in III-nitrides, the properties of iron impurities in the nitrides are not fully established. We investigate the impact of iron impurities on the electrical and optical properties of GaN, AlN, and InN using first-principles calculations based on a hybrid functional. We report formation energies of substitutional and interstitial iron impurities as a function of the Fermi-level position. We also investigate complexes of Fe with substitutional oxygen on the nitrogen site, with nitrogen vacancies and with hydrogen interstitials. In GaN and AlN, iron on the cation site is amphoteric. We discuss the role of the Fe-induced acceptor level and its impact on nonradiative recombination in the context of loss mechanisms in light emitters, and current collapse in high-electron-mobility transistors. In InN, we find the iron interstitial to be the most favorable configuration, where it acts as a shallow double donor.

Deep‐Level Defects and Impurities in InGaN Alloys

“…This explains why the (0/−) charge‐state transition level for these impurities remains constant on an absolute energy scale as a function of indium content. This result is also consistent with our previous observation that the (0/−) levels of C N and Fe Ga are aligned on an absolute scale across all three nitrides (InN, GaN, and AlN) when band alignments are taken into account . The C N (+/0) level is not quite as constant and exhibits a slight upward shift on an absolute energy scale; indeed, for C N in the q = + charge state, the unoccupied state is derived from a hybridization of C and N states.…”

Impact of biaxial and uniaxial strain on V2O3

“…Indeed, we have shown that the presence of point defects in the form of Frenkel pairs disrupts bonding and the magnetic ordering of the V atoms, which in turn leads to a reduction in the energy to transition between the HT paramagnetic metallic phase and the LT antiferromagnetic insulating phase. 5 This is consistent with an experimental observation that found the MIT T c to decrease when point defects are introduced intentionally compared to the T c of as-grown V 2 O 3 . 6 The sensitivity of the MIT to changes in bonding has also made the use of strain an appealing approach to manipulate and control the MIT.…”

“…We have previously shown that the FM ordered monoclinic structure can be used as a suitable proxy for the paramagnetic HT corundum phase. 5 Since strain is defined with respect to the HT phase, we use the lattice constants of the HT ferromagnetic structure as the reference for strain. For example, uniaxial strain along the monoclinic a axis, ǫ a , is defined as: ǫ a = [(a -a 0 )/a 0 ], where a 0 is the equilibrium a lattice constant of the FM monoclinic structure.…”

Defects in Hybrid Perovskites: The Secret of Efficient Charge Transport

“…Such difference was typically observed in semiconductors and was mainly affected by the nature of a particular defect. [ 103 ] Another mechanism responsible for this difference was the effect of phonons on thermal transition probability.…”