Semiconductor Band Structure and Valley-Dependent Transitions Explained #1837997 (License: Personal Use)

The image presents a schematic of a semiconductor heterostructure (part a) and its corresponding band structure (part b), emphasizing valley-selective optical transitions. Energy levels E₁ and E₂ correspond to excitations from K and K′ valleys, where E₁ > E_c indicates a direct transition above the conduction band edge, while E₂ = -E₁ reflects particle-hole symmetry. Arrows denote allowed (checkmark) and forbidden (cross) transitions under circularly polarized light.

Used in academic or technical web pages explaining valleytronics, 2D materials (e.g., transition metal dichalcogenides), or optoelectronic device physics. Matches user intent for learning or researching valley-polarized excitons and selection rules.