Effect of Mn and Mg dopants on vacancy defect formation in ammonothermal GaN

We have applied positron annihilation spectroscopy to study the formation of Ga vacancy related defects in Mg and Mn doped bulk GaN crystals grown by the ammonothermal method. We show that Mn doping has little or no effect on the formation of Ga vacancies, while Mg doping strongly suppresses their formation, in spite of both dopants leading to highly resistive material. We suggest the differences are primarily due to the hydrogen-dopant interactions. Further investigations are called for to draw a detailed picture of the atomic scale phe-nomena in the synthesis of ammonothermal GaN.Peer reviewe

Study of variations of the carrier recombination and charge transport parameters during proton irradiation of silicon pin diode structures

Peer reviewe

SPECTROSCOPY OF DEFECTS IN NEUTRON IRRADIATED AMMONO-THERMAL GaN BY COMBINING PHOTOIONIZATION, PHOTOLUMINESCENCE AND POSITRON ANNIHILATION TECHNIQUES

In this work, pulsed photoionization as well as photoluminescence and positron annihilation spectroscopy were combined to detect different species of defects. The GaN crystals, grown by the ammono-thermal method, doped with Mn as well as Mg impurities and irradiated with different fluences of reactor neutrons, were examined to clarify the role of the technological and radiation defects. The evolution of the prevailing photoactive centres was examined by pulsed photoionization spectroscopy. Positron annihilation spectroscopy was applied to reveal vacancy-type defects.Peer reviewe

Analysis of trap spectra in LEC and epitaxial GaAs

Different methods of trap parameter measurement are analysed. Transient photoconductivity and thermally stimulated effects were used to investigate the influence of traps in LEC SI-GaAs and high resistivity epitaxial GaAs. The peculiarities of the TSC were analysed and shown to be related to the influence of crystal micro-inhomogeneities.Comment: Invited talk, 6-th Workshop on Gallium Arsenide and Related Compounds June 22-26, 1998 Praha-Pruhonice, Czech Republi

RD39 Status Report 2009

RD39 Status Report 2009. CERN RD39 Collaboration is developing super-radiation hard cryogenic silicon detectors for applications of LHC experiments and their future upgrades. The activities of RD39 Collaboration were focused in 2009 on concept of charge injected detector (CID)

ИНЖЕКЦИОННЫЙ ОТЖИГ КОМПЛЕКСА СОБСТВЕННОЕ ДИМЕЖДОУЗЛИЕ – КИСЛОРОД В КРЕМНИИ p-ТИПА

With the use of deep level transient spectroscopy (DLTS) the effect of injection of minority charge carriers (electrons) on an annealing rate of self di-interstitial – oxygen (I2O) complex in silicon has been studied. The complex has been formed by irradiation of epitaxial boron-doped n+–p diode structures with alpha-particles at room temperature. It has been shown that the disappearance of this complex at room temperature begins at a direct current density of ~1.5 A/cm2. This characteristic current density has been found for 10 W·cm p-type silicon when the total radiation defect density was less than 15 % of the initial boron concentration, a divalent hole trap with energy levels of Ev + 0.43 eV and Ev + 0.54 eV has been found to appear as a result of recombination-enhanced annealing of the I2O. When the I2O complex is annealed thermally, the concurrent appearance of an electron trap with an energy level of Ec – 0.35 eV has been observed. It has been shown that the divalent hole trap represents a metastable configuration (BH-configuration) of the bistable defect, whereas the electron trap is stab le in the p-Si configuration (ME-configuration). From the comparison of DLTS signals related to different defect configurations it is found that the ME-configuration of this bistable defect can be characterized as a center with negative correlation energy. It has been shown that the injection-stimulated processes make it very difficult to obtain reliable data on the formation kinetics of the bistable defect in the BH-configuration when studying the thermal annealing of the I2O complex.Методом нестационарной спектроскопии глубоких уровней (DLTS) с использованием n+–p-структур исследовано влияние инжекции неосновных носителей заряда (электронов) на отжиг комплекса собственное димеждоузлие – кислород (I2O) в кремнии, облученном альфа-частицами. Показано, что в легированном бором кремнии, имеющем удельное сопротивление 10 Ом·см, инжекционно-стимулированный отжиг этого комплекса при комнатной температуре начинается при плотности прямого тока ~1,5 А/см2. При этом суммарная концентрация радиационных дефектов не превышала 15 % от начальной концентрации бора. В результате инжекционно-стимулированного отжига I2O образуется двухвалентная дырочная ловушка с уровнями Ev + 0,43 эВ и Ev + 0,54 эВ. Установлено, что в кремнии р-типа проводимости эта ловушка соответствует эмиссии дырок метастабильной конфигурацией бистабильного дефекта (BH-конфигурация). В основной конфигурации (ME-конфигурация) этот бистабильный дефект проявляет себя как электронная ловушка с уровнем Ec – 0,35 эВ. На основании данных об отношении амплитуд сигнала DLTS бистабильного дефекта в различных конфигурациях сделан вывод, что в ME-конфигурации он ведет себя как центр с отрицательной корреляционной энергией. Показано, что наличие инжекционно-стимулированных процес- сов существенно затрудняет получение достоверных данных о кинетике образования бистабильного дефекта в BH-конфигурации при исследовании термического отжига комплекса собственное димеждоузлие – кислород