Observation of electron tunneling induced photon emission in gallium (Ga) doped (1%) zinc oxide (ZnO) sample using scanning tunneling microscopy

Abstract

Electron tunneling induced photon emission in gallium doped (1%) zinc oxide was detected by scanning tunneling microscope in ambient condition. Simultaneously acquired topography and photon maps reveal interesting correlation. Photon maps depict few intense emission spots. Existence of a threshold tunneling current (6 nA) and applied bias (1.8 V), for detectable photon emission was observed. Further analysis of the results suggests Fowler-type photon emission which is ascribed to radiative electron-hole recombination. Localized photon emission spectroscopy exhibits prominent peaks at hν=2.96, 3.43, and 3.80 eV, which match well with the results obtained from photoluminescence studies.

Spatially resolved photoresponse on individual ZnO nanorods: correlating morphology, defects and conductivity

“…It is worth noting that even in the FB regime, at −5 V, the average current in the “high current” region is 10 3 times higher than that in the “low current” region. The rectifying nature of the IV data and the high applied biases that are comparable to the work function (5.1 eV) of Au and the electron affinity (4.2 eV) of ZnO indicate that electrical transport across the tip-sample junction is associated with multiple transport processes ranging from thermionic 29 to field emission 33 . Consequently, the FB IV characteristics were analysed using (i) the thermionic emission (TE) theory, for low biases (|V| < 2 V) and (ii) field emission theory, for |V| > 2 V. Following the standard TE model 34 analysis, Fig.…”

The growth and investigation on Ga-doped ZnO single crystals with high thermal stability and high carrier mobility

“…Hopefully, benefiting from the high lattice integrity, high quality GZO single crystals with high thermal-stability and carrier mobility could not only be a good candidate in the TCE field, but also an ideal research object for insight into the intrinsic physical nature of the GZO material. In the latter, current studies are still based on the multi-crystalline GZO films with a high concentration of defects, [14][15][16][17][18][19][20][21] which causes difficulties to obtain highly reliable and repeatable scientific data. It is anticipated that, with high quality GZO single crystals, some physical phenomena already arousing extensive interest could be further explored.…”