Graphene
Band structure, density of states and electronic properties of graphene nanoribbons
Parameters
Band Structure E(k)
Graphene — Quiz
Q1. Why is graphene a semimetal rather than an ordinary semiconductor?
A
Because it is a very poor conductor
B
Because it has a large band gap
C
At K point valence and conduction bands touch (E_g = 0)
D
Because the number of atoms per unit cell is even
Q2. The flat band at E=0 in zigzag nanoribbon band structure:
A
Is a bulk electron state
B
Are edge-localized states
C
Does not exist
D
Also appears in armchair edge
Q3. Where do Van Hove singularities appear in graphene DOS?
A
E = ±γ₀ (M point)
B
E = 0 (K point)
C
E = ±3γ₀ (Γ point)
D
DOS singularities do not exist in graphene
Q4. Armchair nanoribbon at N = 11 (= 3×4-1):
A
Is semiconducting, E_g > 0
B
Is semiconducting, E_g < 0
C
Has zigzag edge states
D
Is metallic, E_g = 0