Related Experiment Video
Updated: Apr 5, 2026

Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots
Published on: November 1, 2013
Free and bound excitonic effects in Al0.5Ga0.5N/Al0.35Ga0.65N MQWs with different Si-doping levels in the well layers
Chenguang He1, Zhixin Qin1, Fujun Xu1
1State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Abstract:
Free exciton (FX) and bound exciton (BX) in Al0.5Ga0.5N/Al0.35Ga0.65N multiple quantum wells (MQWs) with different Si-doping levels in the well layers are investigated by photoluminescence (PL) spectra. Low temperature (10 K) PL spectra identify a large binding energy of 87.4 meV for the BX in undoped sample, and 63.6 meV for the BX in Si-doped (2 × 10(18 ) cm(-3)) sample. They are attributed to O-bound and Si-bound excitons, respectively. The large binding energies of BX are assumed to originate from the strong quantum confinement in the quantum wells, which also leads to a stronger FX PL peak intensity in comparison with BX at 10 K. Si-doping is found to suppress the FX quenching by reducing threading dislocation density (TDD) in the well layers, leading to a significant improvement of IQE from 33.7% to 45%.
Related Concept Videos
Semiconductors
Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
P-N junction
Types of Semiconductors
Energy Bands in Solids
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
Biasing of Metal-Semiconductor Junctions
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
Metal-Semiconductor Junctions
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...

