Electronic energy states in Si-doped MgO for exoelectron emission

Ho, S.; Nobuki, S.; Uemura, N.; Mori, S.; Miyake, T.; Suzuki, K.; Mikami, Y.; Shiiki, M.; Kubo, S.
July 2009
Journal of Applied Physics;Jul2009, Vol. 106 Issue 1, p14911
Academic Journal
A generalized analytical method to determine the density of energy states of electron emission source (EES) is devised by using a thermal excitation and emission model for an exoelectron in the MgO layer and the emission time constants of the exoelectron extracted from experimental stochastic distributions of discharge delay time. When applied to Si-doped MgO, the emission time constant of the exoelectron from the Si EES becomes shorter at high temperature and at short time intervals due to thermal excitation. The density of energy states of the Si EES DSi(E) shows the main peak at 736 meV, a satellite peak at 601 meV, and broad energy structures over the range of 586–896 meV. The effective number of Si EES is 5.5 times larger than that in purified MgO. The excitation energy in a Si-doped MgO cluster with a crystal structure is obtained to be 0.83 eV by using the symmetry-adapted-cluster configuration interaction method and the Si EES contributes to exoelectron emission. The thermal excitation is governed by the transition from the Si–O bound state and the Mg edge state to the antisymmetrical edge states and the extended surface state. The excitation energy in an MgO cluster with a Si-doped atom inside and a nearest oxygen vacancy taking account of structural relaxation is calculated to be 0.75 eV, which shows good agreement with the main peak in DSi(E). The excitation energies of 0.64, 0.73, and 0.78 eV are also obtained in an MgO cluster with a Si-doped atom at the surface and a nearest oxygen vacancy. The first excitation energy corresponds with the satellite peak. The broad energy structures of DSi(E) are caused by the dependence of excitation energy on the position of Si-doped atoms inside and at the surface of the MgO cluster, and on the interatomic distance of Si–O due to structural relaxation. The energy structures can be also attributed to the thermal excitation to the various symmetrical Mg edge states and the surface states. When the number of complex structures of the Si EES with adjacent oxygen vacancies increases, oxygen vacancies are generated from the complex structures and the increase in the electron traps degrades electron emission rate. Therefore, the number of complex structures has an optimum value that leads to the maximum effective number of Si EES.


Related Articles

  • Effect of Current on the Electroluminescence of Defects Produced by High-Temperature Post-Implantation Annealing of Si : (Er,O) Structures in a Chlorine-Containing Environment. Emel'yanov, A. M.; Shek, E. I. // Physics of the Solid State;Oct2004, Vol. 46 Issue 10, p1810 

    The forward-current dependence of defect-related electroluminescence (EL) in silicon structures produced by erbium and oxygen implantation into silicon single crystals with subsequent annealing in a chlorine-containing ambient at 1100�C has been studied. At 80 K, an increase in the current...

  • A Study of the Zirconium–Oxygen Interaction in Silicon. Pchelintseva, T. S.; Prokof’eva, V. K.; Svetukhin, V. V.; Ambrozevich, A. S.; Rygalin, B. N.; Lysenko, L. N. // Technical Physics Letters;Oct2001, Vol. 27 Issue 10, p852 

    The energy levels created by zirconium in silicon (0.65, 0.52, and 0.32 eV) were determined from the photoconductivity data. The oxygen solubility in zirconium-doped silicon was studied. It was established that zirconium affects the solubility of interstitial oxygen.

  • Defect states in p-type silicon crystals induced by plastic deformation. Ono, Haruhiko; Sumino, Koji // Journal of Applied Physics;1/15/1985, Vol. 57 Issue 2, p287 

    Discusses a study that investigated deep defect states in p-type silicon crystals induced by plastic deformation by means of deep level transient spectroscopy. Kinds of traps having different energy levels within the band gap; Category of the half-filled band model of the dislocation state;...

  • Electronic properties of iron-boron pairs in crystalline silicon by temperature- and injection-level-dependent lifetime measurements. Birkholz, Jens E.; Bothe, Karsten; Macdonald, Daniel; Schmidt, Jan // Journal of Applied Physics;5/15/2005, Vol. 97 Issue 10, p10Q910 

    Iron-boron pairs in crystalline silicon are studied by measuring the recombination lifetime as a function of injection density, doping concentration, and temperature. The characteristic crossover point of the injection-level-dependent carrier lifetime curves measured before and after optical...

  • Optical properties of dislocations in wurtzite ZnO single crystals introduced at elevated temperatures. Ohno, Y.; Koizumi, H.; Taishi, T.; Yonenaga, I.; Fujii, K.; Goto, H.; Yao, T. // Journal of Applied Physics;Oct2008, Vol. 104 Issue 7, p073515 

    Optical properties of wurtzite ZnO bulk single crystals in which an arbitrary number (typically 109–1010 cm-2) of fresh dislocations were introduced intentionally by the plastic deformation at elevated temperatures (923–1073 K) were examined. Deformed specimens showed excitonic...

  • Effects of high temperature annealing on single crystal ZnO and ZnO devices. Mtangi, W.; Auret, F. D.; Diale, M.; Meyer, W. E.; Chawanda, A.; de Meyer, H.; Janse van Rensburg, P. J.; Nel, J. M. // Journal of Applied Physics;Apr2012, Vol. 111 Issue 8, p084503 

    We have systematically investigated the effects of high-temperature annealing on ZnO and ZnO devices using current voltage, deep level transient spectroscopy (DLTS) and Laplace DLTS measurements. Current-voltage measurements reveal the decrease in the quality of devices fabricated on the...

  • Rectification properties of n-type nanocrystalline diamond heterojunctions to p-type silicon carbide at high temperatures. Goto, Masaki; Amano, Ryo; Shimoda, Naotaka; Kato, Yoshimine; Teii, Kungen // Applied Physics Letters;4/14/2014, Vol. 104 Issue 15, p153113-1 

    Highly rectifying heterojunctions of n-type nanocrystalline diamond (NCD) films to p-type 4H-SiC substrates are fabricated to develop p-n junction diodes operable at high temperatures. In reverse bias condition, a potential barrier for holes at the interface prevents the injection of reverse...

  • Energy level alignment at Co/AlOx/pentacene interfaces. Popinciuc, M.; Jonkman, H. T.; van Wees, B. J. // Journal of Applied Physics;5/1/2007, Vol. 101 Issue 9, p093701 

    X-ray and ultraviolet photoemission spectroscopy (XPS and UPS) experiments were performed in order to study the energy level alignment and electronic structure at Co/AlOx/pentacene interfaces as a function of the aluminum oxide (AlOx) tunnel barrier thickness and the oxidation state of Co. XPS...

  • Determining the energy levels of elementary primary defects in silicon. Luk’yanitsa, V. V. // Semiconductors;Aug99, Vol. 33 Issue 8, p842 

    The purpose of the experiments described here was to determine the energy level spectrum of elementary primary Frenkel defects in the band gap of silicon, based on whether or not the rate of direct annihilation of these defects depends on their charge state. The results were obtained by jointly...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics