Page 178 - Electrical Properties of Materials
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160 Semiconductors
(i) How many distinct types of charge carriers do there (iv) If the figure were not labelled would you be able to tell
appear to be in Ge from this data? which peaks referred to electrons?
(ii) How many types of charge carriers are really there? How (v) Estimate the collision times of the holes [Hint: Use
would you define whether they are ‘real’ charge carriers eqn (1.61)].
or not? (vi) Estimate the relative number density of the holes.
(iii) What are the effective masses for this particular crystal (vii) In Section 8.8 we talked about three different types
direction? Can this effective mass be directly interpreted of holes. Why are there only two resonance peaks for
for electrons? For holes? holes?
