Photocurrents in nanotube junctions

TL;DR

This paper models photocurrents in nanotube p-n junctions using quantum transport formalism, revealing size-dependent effects, spectral peaks, and the influence of density of states on photoresponse.

Contribution

It introduces a quantum transport approach to analyze photocurrents in nanotube junctions, highlighting size effects and spectral features not previously detailed.

Findings

Photocurrent peaks in infrared, visible, and ultraviolet ranges.

Size effects cause photocurrent to oscillate with device length.

Density of states influences the magnitude of photoresponse.

Abstract

Photocurrents in nanotube p-n junctions are calculated using a non-equilibrium Green function quantum transport formalism. The short-circuit photocurrent displays band-to-band transitions and photon-assisted tunneling, and has multiple sharp peaks in the infrared, visible, and ultraviolet ranges. The operation of such devices in the nanoscale regime leads to unusual size effects, where the photocurrent scales linearly and oscillates with device length. The oscillations can be related to the density of states in the valence band, a factor that also determines the relative magnitude of the photoresponse for different bands.