Stability of Magnesium-Incorporated Semipolar GaN(10\bar1\bar1) Surfaces

Abstract

The stability of Mg-incorporated GaN surfaces with semipolar ( 101 1 1 1) orientation is investigated by performing first-principles pseudopotential calculations. Several Mg-incorporated surfaces, in which a single Mg atom is substituted for the topmost Ga atom, can be formed when the surfaces include step edges in the [0 1 100] direction. This implies that on the stepped surfaces Mg atoms can be easily incorporated into electrically active substitutional lattice sites, leading to high hole concentrations. The calculated results provide a possible explanation for experimentally observed high hole concentrations in Mg-doped semipolar ( 101 1 1 1) GaN on vicinal (100) MgAl 2 O 4 substrates miscut in the h011i direction.

Surface Stability and Growth Kinetics of Compound Semiconductors: An Ab Initio-Based Approach

“…A thermodynamic approach that includes chemical potentials that are appropriate for realistic growth conditions has revealed that hydrogen stabilizes Mg-rich surface reconstructions for both GaN(0001) and $false(1\overline{1}00false)$ surfaces [135]. In addition, the stability of the Mg-incorporated GaN$false(1\overline{1}0\overline{1}false)$ surface has been examined [40] to explain high hole concentrations in the Mg-doped semipolar GaN$false(1\overline{1}0\overline{1}false)$ surface [136]. …”

Recent Progress in Computational Materials Science for Semiconductor Epitaxial Growth

“…The power of this approach is not only on understanding the epitaxial growth processes but also on producing fundamental data such as surface phase diagrams as functions of growth conditions. Surface phase diagrams and elemental growth processes have been extensively investigated using similar approach for various semiconductors except InAs and InP such as GaAs [18,41,[103][104][105][106][107][108] and III-Nirides [7][8][9][109][110][111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126][127][128]. Figure 36 summarizes the calculated surface phase diagrams with different orientations for AlN and GaN under H-rich conditions during MOVPE growth.…”

Ab initio-Based Approach to Crystal Growth

“…I I is written as 11.9) where m I is the reduced mass and r is the radius of gyration. The detailed procedure in the total energy calculations has been reported elsewhere [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. In the total energy calculations for the compound semiconductor surfaces with various atomic arrangements, we used the ab initio pseudopotential method based on the local-density functional formalism [9] within the generalized gradient approximation [10].…”

“…Generally, blue light-emitting diodes (LEDs) and laser diodes (LDs) using III-nitrides are fabricated on the (0001)-polar surface. Since the demonstration of InGaN/GaN LEDs on semipolar (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) bulk GaN [94,95], the (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) plane has been the most promising among the semipolar orientations. This is because there are large internal piezoelectric fields in the III-nitride layers grown on the (0001) heterosubstrates.…”

“…Recently, III-nitrides growth on nonpolar and semipolar surfaces has attracted increasing attention. Unlike the conventional GaN growth along the [0001] direction, lower temperatures (870-975 C) are found to be required to obtain atomically flat (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) surfaces in MOVPE [7] and hydride vapor-phase epitaxy [95]. The large internal piezoelectric fields separate electrons and holes to opposite interfaces of the layer.…”