Size dependent tunneling and optical spectroscopy of CdSe quantum rods

TL;DR

This study investigates how the electronic and optical properties of CdSe quantum rods depend on their size, particularly diameter, revealing a transition from zero to one-dimensional quantum confinement through spectroscopy and modeling.

Contribution

It provides a detailed analysis of size-dependent electronic states in CdSe quantum rods using combined optical spectroscopy, tunneling measurements, and theoretical modeling.

Findings

Level structure depends mainly on rod diameter

Band-gap and excited state spacings shift to red with increasing diameter

Multi-band effective-mass model explains size dependence

Abstract

Photoluminescence excitation spectroscopy and scanning tunneling spectroscopy are used to study the electronic states in CdSe quantum rods that manifest a transition from a zero dimensional to a one dimensional quantum confined structure. Both optical and tunneling spectra show that the level structure depends primarily on the rod diameter and not on length. With increasing diameter, the band-gap and the excited state level spacings shift to the red. The level structure was assigned using a multi-band effective-mass model, showing a similar dependence on rod dimensions.