Hole concept: motion of a vacant electronic state Consider the statement: “A vacant electronic state (a hole) moves in the same direction as a positive charge carrier would.” Determine whether this is true in semiconductor physics and briefly justify.

Introduction / Context:
The hole model is a powerful abstraction in semiconductor physics. Instead of tracking many electrons in a nearly filled valence band, we track the dynamics of the missing electron (hole), which behaves as a positive carrier. Correctly interpreting its direction of motion under fields is crucial for understanding current flow in diodes and transistors.

Given Data / Assumptions:

• Valence band nearly full; conduction due to a small number of vacancies (holes).
• Applied electric field within the crystal lattice.
• Semi-classical transport picture applies.

Concept / Approach:

When an electron in the valence band moves one site to the right, it leaves a vacancy one site to the left. A sequence of such electron moves makes the vacancy appear to drift opposite to electron motion. Since electrons (negative charges) accelerate opposite to the electric field, the vacancy (hole) is observed to move along the electric field direction—exactly like a positive charge carrier.

Step-by-Step Solution:

Verification / Alternative check:

Hall-effect measurements in p-type semiconductors show positive Hall coefficients, indicating positive effective charge carriers moving with the field, validating the hole picture.

Why Other Options Are Wrong:

Limiting the truth to metals or extrinsic cases is unnecessary; the hole concept applies broadly whenever the valence band is not completely full.

Common Pitfalls:

Confusing conventional current direction with electron flow; forgetting that the hole is a convenient quasiparticle description but has real measurable effects (e.g., mobility, effective mass).

Final Answer:

True