In semiconductor physics, “holes” in a crystal lattice behave electrically as what kind of charge carriers?

Introduction / Context:
Understanding how “holes” behave is foundational to semiconductor devices such as diodes, bipolar junction transistors, and integrated circuits. While holes are not physical particles like electrons, their effective behavior in a crystal matters for current flow and device modeling.

Given Data / Assumptions:

• A “hole” is the absence of an electron in the valence band.
• Materials considered: intrinsic or doped semiconductors (e.g., silicon).
• We focus on the electrical behavior (effective charge and motion) rather than atomic structure.

Concept / Approach:
A missing electron in a covalent bond leaves a vacancy that can be filled by a neighboring electron. This movement of vacancies can be modeled as mobile positive charge carriers. In P-type material, holes are the majority carriers and drift in the direction of the applied electric field, opposite to electron motion, producing conventional current.

Step-by-Step Solution:
Define a hole as the absence of a valence electron.Recognize that when electrons move to fill vacancies, the vacancies appear to move.Model this vacancy as a carrier with positive charge.Select “Positive charges.”

Verification / Alternative check:
Device equations (e.g., diode current equation, transistor action) treat hole concentration and mobility similarly to electrons but with positive charge sign, confirming the effective positive behavior.

Why Other Options Are Wrong:
A/B: Atoms or crystals are not carriers; these describe structures, not charge types. C: Holes are not negative; electrons are negative. E: Not applicable since a correct choice exists.

Common Pitfalls:
Thinking holes are literal particles; forgetting that current direction is defined by positive charge flow (conventional current), which holes represent effectively.

Final Answer:
Positive charges