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Study of consecutive processes by means of adsorption calorimetry
A413 Surface Science 134 (1983) 135-144 North-Holland Publishing Company
135
TWO-DIMENSIONAL DENSITY OF STATES FOR ELECTRONS BOUND TO IMPURITIES INSIDE INVERSION LAYERS AT THE SEMICONDUCTOR-INSULATOR INTERFACE * I.C. D A C U N H A M. FABBRI
L I M A **, A. F E R R E I R A
DA SILVA and
lnstituto de Pesquisas Espaciais (1NPE), Conselho Nacional de Desenvolvimento Cientifico e Tecnol~gico CNPq, 12200 Sao Jos~ dos Campos, SP, Brazil *** and Department of Physics, Brown University, Providence, Rhode Island 02912, USA Received 28 December 1982; accepted for publication 28 July 1983
The density of states for electrons bound to Na + impurities inside the inversion layer at the semiconductor-insulator interface of an MOS structure is calculated as a function of impurity concentration. The impurity potential is considered unscreened and the electrical quantum limit is assumed. A simple one-electron Hamiltonian is used and the disorder is treated through a cluster calculation. It is shown that the impurity band has a considerable bandwidth for impurity concentrations in a range of the experimental regime (this result agrees with the experimental findings of Hartstein and Fowler), and that the upper Hubbard band stands well above the lower band at very low concentration (in rough agreement with r~ent calculation done by Phelps and Bajaj on D - state).
Surface Science 134 (1983) 145-160 North-Holland Publishing Company
145
STUDY OF CONSECUTIVE CALORIMETRY
PROCESSES
C. P L U N T K E ,
* and G. RAU
G. WEDLER
BY MEANS
OF ADSORPTION
Institut fi~r Physikalische und Theoretische Chemie der Universitiit Erlangen-Ni~rnberg, Egerlandstrasse 3, D - 8520 Erlangen, Fed. Rep. of Germany Received 2 May 1983; accepted for publication 27 July 1983
Experiments using an isoperibolic (diathermal) adsorption calorimeter show that in some adsorption systems there is an exothermic or endothermic consecutive process following the primary adsorption step. For the simple case of a consecutive process of first order it is possible to derive as well the kinetic as the energetic parameters describing the formation of the intermediate and final adsorption state.
135
TWO-DIMENSIONAL DENSITY OF STATES FOR ELECTRONS BOUND TO IMPURITIES INSIDE INVERSION LAYERS AT THE SEMICONDUCTOR-INSULATOR INTERFACE * I.C. D A C U N H A M. FABBRI
L I M A **, A. F E R R E I R A
DA SILVA and
lnstituto de Pesquisas Espaciais (1NPE), Conselho Nacional de Desenvolvimento Cientifico e Tecnol~gico CNPq, 12200 Sao Jos~ dos Campos, SP, Brazil *** and Department of Physics, Brown University, Providence, Rhode Island 02912, USA Received 28 December 1982; accepted for publication 28 July 1983
The density of states for electrons bound to Na + impurities inside the inversion layer at the semiconductor-insulator interface of an MOS structure is calculated as a function of impurity concentration. The impurity potential is considered unscreened and the electrical quantum limit is assumed. A simple one-electron Hamiltonian is used and the disorder is treated through a cluster calculation. It is shown that the impurity band has a considerable bandwidth for impurity concentrations in a range of the experimental regime (this result agrees with the experimental findings of Hartstein and Fowler), and that the upper Hubbard band stands well above the lower band at very low concentration (in rough agreement with r~ent calculation done by Phelps and Bajaj on D - state).
Surface Science 134 (1983) 145-160 North-Holland Publishing Company
145
STUDY OF CONSECUTIVE CALORIMETRY
PROCESSES
C. P L U N T K E ,
* and G. RAU
G. WEDLER
BY MEANS
OF ADSORPTION
Institut fi~r Physikalische und Theoretische Chemie der Universitiit Erlangen-Ni~rnberg, Egerlandstrasse 3, D - 8520 Erlangen, Fed. Rep. of Germany Received 2 May 1983; accepted for publication 27 July 1983
Experiments using an isoperibolic (diathermal) adsorption calorimeter show that in some adsorption systems there is an exothermic or endothermic consecutive process following the primary adsorption step. For the simple case of a consecutive process of first order it is possible to derive as well the kinetic as the energetic parameters describing the formation of the intermediate and final adsorption state.