TEM investigation of modulated structures and ordered structures in InAlAs crystals grown on (001) InP substrates by molecular beam epitaxy

Kinetic instability of semiconductor alloy growth

“…Observations of composition-modulated structures refer to as-grown samples, and there are no experimental data on the formation of composition-modulated structures via annealing of a semiconductor alloy. Such modulated structures have been observed in III-V semiconductor alloys grown by liquid-phase epitaxy, 25-31 by vapor-phase epitaxy, 32 by metal-organic vapor phase epitaxy, [33][34][35] and by molecular-beam epitaxy, 30,34,36 and in II-VI semiconductor alloys grown by MBE. 37 Bulk diffusion coefficients in semiconductors are several orders of magnitude smaller than those in metals.…”

“…Experimental data indicate a number of compositionmodulated structures which are formed both in III-V semiconductor alloys in the process of liquid phase epitaxy, [25][26][27][28][29][30][31] in the process of chemical vapor deposition, [32][33][34][35] and in the process of molecular-beam epitaxy ͑MBE͒, 30,34,36 and in II-VI semiconductor alloys in the process of MBE. 37 The difference between metal alloys and semiconductor alloys in formation mechanisms and conditions for the observation of composition-modulated structures is discussed in Sec.…”

Ordering at Surfaces and Interfaces

“…In addition to the classical model of Langmuir [I], recent pseudopotential calculations [29,30] on the Na/Si(lll), K/Si(IOO)2xl,K/Si(lll)2xl and Na/Si(IOO)2xl systems found a very short K-Si bond length at 2.59 A for the K/Si(IOO)2xl system, resulting in a very strong ionic bonding with a complete charge transfer to the surface and silicon surface metallization [30]. The K-Si distance was measured experimentally by SEXAFS to be 3.14 A at one K monolayer which corresponds to the exact sum of K and Si covalent radii [35]. The K-Si distance was measured experimentally by SEXAFS to be 3.14 A at one K monolayer which corresponds to the exact sum of K and Si covalent radii [35].…”

“…This behavior is typical of the formation of an electronic interface state (peak C). Because of the low temperatures of desorption of alkali metals, 550°C for Na [23,24,37], 600°C for K [35,38,39], 650°C for Rb [37,39] and Cs [23,24,37], the covalent bonding between alkali metal and silicon atoms is weak. The only two possible candidates in this energy range are the Si 3p and Na 3s valence electrons.…”

Simultaneous existence and atomic arrangement of CuPt-type and CuAu-I type ordered structures near ZnTe/ZnSe heterointerfaces

“…Some studies concerning several kinds of ordered structures in ternary semiconductors, such as CuAu, [12][13][14] chalcopyrite, [15][16][17] and CuPt, 18 -20 have been reported. However, studies concerning the origins of the coexistence of ordered structures in group II-VI/III-VI heterostructures have not been performed yet.…”