EPR and ODMR defect control in AlN bulk crystals

Abstract

The results of pulse electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR) and optically detected magnetic resonance (ODMR) are presented to show the electron structure of deep level defect color center in AlN single crystals such as a nitrogen vacancy in neutral charge state (VN0) as well as a new type of point defect such as exchange–coupled pair of the nitrogen vacancies (VN‐VN). Analyzing spin density distribution of an unpaired VN0 electron on different ions of AlN crystalline lattice by means of high frequency ENDOR technique (94 GHz) give us a possibility to calculate hyperfine and quadrupole interactions (QI) with 27Al nuclei spins up to fourth coordinate sphere. Particularly data about quadrupole interactions allowed to estimate the fundamental parameter of AlN crystalline lattice in itself namely so called «crystalline field gradient» to be 4.9×1020V/m2 (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Design of defect spins in piezoelectric aluminum nitride for solid-state hybrid quantum technologies

“…These findings indicate that the S = 3/2 state of V N 2− might be of potential interest as a defect qubit, but it might be difficult to realize, as highly n- doped w- AlN is difficult to obtain 47 48 . Interestingly, the V N 0 S = 1/2 state has been recently detected using electron paramagnetic resonance 18 19 . Based on these results, we considered the Fermi level range in the vicinity of the stability region of V N 0 , which might be accessible in experiments.…”

“…We found that negatively charged nitrogen vacancies exhibit localized spin-triplet states in n- type aluminum nitride under realistic strain conditions. Nitrogen vacancies are naturally incorporated in aluminum nitride during crystal growth and they are known to be the main source of the intrinsic n- type behavior of aluminum nitride 18 19 20 21 , thus making the nitrogen vacancy spins easily amenable to experimental investigations 18 19 . Extra n- type doping control might be achievable by introducing substitutional oxygen impurities (O N ) during crystal growth 24 .…”

“…[28], is 24% [28], which justifies the use of the PBE0 hybrid functional, whose mixing parameter is defined to be 25% (see below). We examined the most common native defects, which may be easily accessible in experiment (including Al [22,23] and N vacancies [18,19], O impurities [24], and cation-anion defect complexes [23,25]). To mimic the presence of isolated defects, we employed supercells with 480 and 96-atoms, when using the PBE and PBE0 approximations, respectively, and full geometry optimizations were performed with both functionals.…”

“…In an ionic solid, the energy of defect states derived from dangling bonds is usually close to either the conduction or the valence band edge and, in many cases it may be in strong resonance with that of the bulk band edges [6]. In the case of w-AlN, another critical constraint stems from doping: this material is naturally n-type, similar to several other nitrides [18][19][20], and attaining stable p-type doping is extremely challenging [21][22][23][24][25], effectively constraining the search for a defect qubit to n-type w-AlN.…”

Комбинационное рассеяние света в кристаллах AlN, выращенных методом сублимации на затравках SiC и AlN

“…Первоначально этот метод использовался для выращивания кристаллов SiC [1], а позднее был успешно применен и для А1N [2]. Высокое качество получаемых этим методом кристаллов А1N было подтверждено их микроскопическими, оптическими, рентгеновскими исследованиями [2], а также изучением электронного парамагнитного резонанса [3]. Позднее удалось дополнительно повысить качество выращиваемых кристаллов за счет испарения затравки непосредственно в ходе процесса роста, что позволило избежать их растрескивания и образования микротрещин в результате процесса послеростового остывания [4].…”