ELECTRONIC-STRUCTURE OF HYDROGENATED AMORPHOUS-SILICON GERMANIUM ALLOYS STUDIES BY X-RAY PHOTOELECTRON-SPECTROSCOPY AND SOFT-X-RAY SPECTROSCOPY

被引:13
作者
SENEMAUD, C
ARDELEAN, I
机构
[1] Lab. de Chimie-Physique, Univ. Pierre et Marie Curie, Paris
关键词
D O I
10.1088/0953-8984/2/44/002
中图分类号
O469 [凝聚态物理学];
学科分类号
070205 ;
摘要
The authors present a study of Si 2p and Ge 3d core levels and of the valence Si 3p and conduction Si p and Ge s,d states by, respectively, X-ray-induced photoelectron spectroscopy and soft X-ray emission and absorption spectroscopy, for hydrogenated amorphous silicon-germanium a-Si 1-xGex:H alloys with 0.16<x<0.60 prepared by the glow-discharge technique. As the Ge concentration increases, the core level distributions are gradually broadened; they attribute this effect to an increase in the local disorder by alloying. The low-binding-energy edge of the valence p distribution is shifted towards EF while the bottom of the conduction band remains at the same energy position. Thus they clearly show that the decrease in the optical gap as xGe increases is only due to a shift of the valence band edge. At the bottom of the conduction band, Si p and Ge s,d empty states are totally mixed; a spreading of the edge is observed as the Ge concentration increases. Eventually, the X-ray emission of a core excitonic state is observed as a faint structure in the Si K beta spectra, for xGe=0.45 and 0.60.
引用
收藏
页码:8741 / 8750
页数:10
相关论文
共 23 条
[1]  
BULLOT J, 1988, 8TH P COMM EUR COMM, V2, P1220
[2]  
CABARROCAS PRI, 1987, 7TH P COMM EUR COMM, P583
[3]   ELECTRONIC-STRUCTURE OF AMORPHOUS SI1-XGEX-H ALLOYS STUDIED BY SOFT-X-RAY AND PHOTOELECTRON SPECTROSCOPIES [J].
CARDINAUD, C ;
SENEMAUD, C ;
VILLELA, G .
JOURNAL OF NON-CRYSTALLINE SOLIDS, 1986, 88 (01) :55-65
[4]   X-RAY-EMISSION FROM CORE EXCITONS [J].
CARSON, RD ;
SCHNATTERLY, SE .
PHYSICAL REVIEW LETTERS, 1987, 59 (03) :319-322
[5]   STUDIES OF THE DENSITY OF STATES AT THE BAND EDGES AND IN THE PSEUDO-GAP IN A-SIGE-H ALLOYS BY COMBINED PHOTOTHERMAL DEFLECTION SPECTROSCOPY AND X-RAY SPECTROSCOPY [J].
CHAHED, L ;
GHEORGHIU, A ;
THEYE, ML ;
ARDELEAN, I ;
SENEMAUD, C ;
GODET, C .
JOURNAL OF NON-CRYSTALLINE SOLIDS, 1989, 114 :471-473
[6]  
CHAHED L, 1983, SOLID STATE COMMUN, V45, P648
[7]  
CHAHED L, 1988, 8TH P EC PHOT SOL EN, V1, P846
[8]  
DREVILLON B, 1986, PHILOS MAG B, V24, P335
[9]  
EIKE A, 1989, J NONCRYST SOLIDS, V114, P474
[10]  
EVANGELISTI F, 1984, PHYS REV LETT, V53, P2505