Nanopipes in Thick GaN Films Grown at High Growth Rate

In this work we illustrate and describe long propagating nanopipes in thick HVPE‐GaN layers analysed by means of transmission electron microscopy. They are observed to behave like screw component threading dislocations, terminating surface steps by hexagonal pits, and thus leading to the possibility of spiral growth. The formation of a nanopipe is observed by trapping of a screw dislocation at a pinhole that opens in an empty core. The mechanism of formation of nanopipes is likely to be connected to the growth kinetics of screw dislocations in the early stages of growth of highly strained material.