Atomistic study of electronic structure of PbSe nanowires

TL;DR

This study investigates how the size and orientation of PbSe nanowires affect their electronic bandstructure using tight-binding theory, revealing size-dependent bandgap changes and orientation-specific conductance differences.

Contribution

It provides a detailed analysis of the size and orientation effects on PbSe nanowire electronic properties using an 18-band tight-binding model, which is novel in this context.

Findings

Bandgap increases inversely with nanowire width W.

[111] and [110] NWs have higher ballistic conductance than [100] NWs.

Significant splitting of L-valleys in [100] NWs affects conductance.

Abstract

Lead Selenide (PbSe) is an attractive `IV-VI' semiconductor material to design optical sensors, lasers and thermoelectric devices. Improved fabrication of PbSe nanowires (NWs) enables the utilization of low dimensional quantum effects. The effect of cross-section size (W) and channel orientation on the bandstructure of PbSe NWs is studied using an 18 band $sp^3d^5$ tight-binding theory. The bandgap increases almost with the inverse of the W for all the orientations indicating a weak symmetry dependence. [111] and [110] NWs show higher ballistic conductance for the conduction and valence band compared to [100] NWs due to the significant splitting of the projected L-valleys in [100] NWs.