Pre-breakdown characteristics in thin films of amorphous semiconductor of As
30-Te
48-Ge
10-Si
12 (atomic %) system are inverstigated. Thin film samples of sandwich type structure are used as metal electrodes. Two types of transition current
I with applied voltage
V are observed by the difference of metal used as the electrode. When Au or Ni is chosen as electrode,
I-
V characteristics are found to vary as
I∝
V1.5-2 after following Ohm's law, and when Al is chosen as electrode, current varies as V
L+1 where L is a constant. Possibility of conduction mechanisms for the
I∝
V1.5-2 relation are qualitatively discussed. The
I∝
VL+1 relation based on the theory of space charge limited current dominated by exponential distribution of traps are also discussed. In the discussion, values used for concentration of traps and electron mobility are _??_10
15-16cm
-3 and _??_10
-4 cm
2 V
-1 sec
-1, respectively. These values are applicable for amorphous materials.
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