Indentation-induced dislocations and cracks in (0001) freestanding and epitaxial GaN

On the luminescence of freshly introduced a-screw dislocations in low-resistance GaN

“…We note that images of deeper curvilinear dislocation loops appeared in the CL maps near the growth surface indents at high accelerating voltages, which were seen as dark lines with a contrast of 2.5-5% in all modes in accordance with previously published data [18].…”

“…In the case of monochromatic measurements, freshly introduced screw dislocations in the exciton CL band had dark contrast as reported previously [8,9,17]; in the panchromatic mode, the bright con trast of screw dislocations reached 20-30% at an accelerating voltage of V a = 5 kV. We note that images of deeper curvilinear dislocation loops appeared in the CL maps near the growth surface indents at high accelerating voltages, which were seen as dark lines with a contrast of 2.5-5% in all modes in accordance with previously published data [18].…”

“…According to the TEM data [9,13], these luminous lines are screw disloca tions in small half loops with head edge dislocations in the prismatic and basal slip systems with the Burgers vector (a/3) 〈2 0〉.…”

“…Experimental data on the effect of dislocations on GaN luminescence, obtained until recently revealed both the nonradiative nature of recombination at dis locations and the appearance of new spectral lumines cence bands [6][7][8][9][10].…”

Hardness control for improvement of dislocation reduction in HVPE-grown freestanding GaN substrates

“…2(a). The formation of similar dislocation lines along the o11-204 direction at the loading point of micro-indentation for freestanding GaN substrate has also been reported by Ratschinski et al [15].…”