Low-angle boundaries in ZnGeP₂single crystals

Abstract

The structure of low-angle boundaries in ZnGeP 2 crystals grown by the vertical Bridgman technique was studied using Borrmann X-ray topography. The slip systems of the dislocations in the boundaries were identified by studying the contrast rosettes generated by the Borrmann effect, in the region near the dislocation core. It was shown that the boundaries are of two types: type I consists of edge dislocations of the {110}h110i slip system, and type II of edge and mixed dislocations of the {010}h100i slip system. The boundaries of both types, consisting of pure edge dislocations with lines along [001], are symmetrical tilt boundaries with [001] rotation axes. The misorientations generated by the boundaries were estimated to range between 2-20 and 1-40 00 , respectively. Lowangle boundaries are thought to be formed by polygonization of dislocations, caused by thermoelastic stresses.

Structural defects in ZnGeP2single crystals revealed by X-ray topography

“…11(b). Comprehensive analysis of the low-angle boundary structure formed in ZnGeP 2 crystals was presented in our recent paper (Lei et al, 2018). Thus, the position of the peak has changed monotonically, and the largest deviation at 0 mm was almost 300 00 .…”

“…In fact, few data on the slip systems and possible Burgers vectors are available for chalcopyrite (Murr & Lerner, 1977;Couderc & Hennig-Michaeli, 1986). The Burgers vectors and slip systems have been analysed for chalcopyrite in a few of our recent papers (Okunev & Verozubova, 2015;Okunev et al, 2009;Lei et al, 2018). In the present paper, we study structural defects and their distribution in ZnGeP 2 single crystals by the methods of X-ray diffractometry and topography.…”

Structural Analysis of Low Defect Ammonothermally Grown GaN Wafers by Borrmann Effect X-ray Topography

“…So far, XRT using the Borrmann effect has been reported mainly for highly absorbing crystals of semiconductors such as Ge [ 24 ], GaAs [ 25 , 26 ], CdTe [ 27 ] and ZnGeP 2 [ 28 , 29 , 30 ], as well as the electro-optical material KH 2 PO 4 [ 17 ]. In this paper we apply this method for three 1.8 inch highly conductive Am-GaN substrates.…”

Методы Рентгеновской Дифракционной Топографии (О Б З О Р)

“…Такие розетки образуются, если в условии бормановской дифракции направление преимущественного распространения энергии рентгеновского волнового поля совпадает с направлением дислокационной линии. Техника розетки очень удобна, если дислокации в кристалле расположены вдоль основных кристаллографических направлений [181]. Идентификация дефектов структуры облегчается возможностью моделирования теоретического контраста дефектов структуры, основанного на полуфеноменологической теории контраста [56] и цифровой обработке экспериментального контраста, направленной на повышение его качества и устранение основных зашумляющих факторов, таких как слабая контрастность, фоновая неоднородность и зернистость фотоэмульсии [128].…”