Scattering of electrons at threading dislocations in GaN

Abstract

A model to explain the observed low transverse mobility in GaN by scattering of electrons at charged dislocation lines is proposed. Filled traps along threading dislocation lines act as Coulomb scattering centers. The statistics of trap occupancy at different doping levels are investigated. The theoretical transverse mobility from Coulomb scattering at charged traps is compared to experimental data. Due to the repulsive potential around the charged dislocation lines, electron transport parallel to the dislocations is unaffected by the scattering at charged dislocation lines.

The influence of nitridation time on the structural properties of GaN grown on Si (111) substrate

“…Large lattice mismatch with respect to the substrate commonly causes high dislocation densities in heteroepitaxial thin films [18][19][20][21]. These types of structures are often described by the model of mosaic crystals [20,22].…”

Fabrication and characterization of nano‐porous GaN template for strain relaxed GaN growth

“…Discreet threading dislocations, as observed by TEM and AFM studies, define the sub-grain boundary or the columnar structure in GaN epilayers [8]. The threading dislocations serve as traps for the photo-generated carriers, creating regions of reduced etch rate [9]. Figure 1 shows a high magnification image of fabricated porous GaN by scanning electron microscope (SEM).…”

Characterization of low-frequency noise in molecular beam epitaxy-grown GaN epilayers deposited on double buffer layers

“…22 As discussed earlier, the relation between the carrier mobility and the dislocation density of the GaN films can be explained by the proposed dislocation model. 18 However, the relation between the polarity of GaN film and carrier mobility ͑or dislocation density͒ is still not certain to date. 23 It is well known that Ga-faced GaN has superior surface morphology compared to N-faced GaN.…”

“…A dislocation model had been proposed by Weimann et al 18 to account for the low electron mobility in GaN epilayers. The model takes into the consideration that negatively charged threading dislocations with an edge component act as Coulomb scattering centers.…”