Defect states of hydrogenated nanocrystalline silicon studied by surface photovoltage spectroscopy

Surface photovoltage spectroscopy (SPS) is used to determine the defect states of the nc-Si:H films which are prepared by using helicon wave plasma-enhanced chemical vapor deposition technique(HWP-CVD) under different substrate temperature. The films exhibit a 3-phase model, which suggests that nc-Si:H consists of crystalline grains surrounded by grain boundaries and embedded in an amorphous matrix. SPS measurement indicated that the nc-Si:H films have additional two types of additional defect states besides the occupied Si dangling bond states D0/Di and the empty Si dangling states D+ in a-Si, which is attributed to the interface defect states between the nanocrystalline Si grains and the amorphous matrix. The relative SPS intensity of these two kinds of defect states in samples increases with the temperature, which may be interpreted as a result of the bonded hydrogen release at the surface of nanocrystalline Si grains and in the amorphou matrix while increasing substrate temperature.

[1]  Xiaodong Li,et al.  Remote plasma chemical vapour deposition of silicon films at low temperature with H-2 and He plasma gases , 1999 .

[2]  David Cahen,et al.  Determination of undoped CdTe(111) surface polarity by surface photovoltage spectroscopy , 1994 .

[3]  Electrical characterization of N-type nanocrystalline silicon on p-type crystalline silicon (nc-Si:H/c-Si) heterojunctions , 2000 .

[4]  Warren B. Jackson,et al.  Density of gap states of silicon grain boundaries determined by optical absorption , 1983 .

[5]  Andrew G. Glen,et al.  APPL , 2001 .

[6]  H. Gatos,et al.  Surface photovoltage spectroscopy - A new approach to the study of high-gap semiconductor surfaces. , 1973 .

[7]  Chen Kun-ji,et al.  TRANSPORT PROPERTIES OF µc-Si:H FILMS PREPARED BY VERY HIGH HYDROGEN-DILUTED SILANE PLASMA * , 2001 .

[8]  Qi Wang,et al.  Raman study of thin films of amorphous-to-microcrystalline silicon prepared by hot-wire chemical vapor deposition , 2003 .

[9]  Yoshihiko Kanemitsu,et al.  Evidence of quantum size effect in nanocrystalline silicon by optical absorption , 2001 .

[10]  X. S. Wu,et al.  Transport mechanism of nanocrystalline-silicon film tunnelling diodes , 1999 .

[11]  A. Matsuda.  Formation kinetics and control of microcrystallite in μc-Si:H from glow discharge plasma , 1983 .

[12]  Enhanced optical absorption in hydrogenated microcrystalline silicon: an absorption model , 1998 .

[13]  W. Spear,et al.  Some new results on transport and density of state distribution in glow discharge microcrystalline silicon , 1983 .