Indium incorporation and optical transitions in InGaN bulk materials and quantum wells with arbitrary polarity

Abstract

Indium incorporation into strained InGaN coherently grown on a GaN substrate with arbitrary polarity is simulated using a simplified epitaxy model. The InGaN composition is predicted as a function of C-axis inclination angle. Effect of strain originated from the lattice mismatch on optical transitions in the bulk InGaN and quantum wells is examined with account of both complex valence band structure and polarization charges induced at the InGaN/GaN interfaces. A higher indium incorporation on nonpolar and semipolar planes, as compared to the ordinary C-plane, is found to not necessarily result in a longer emission wavelength.

Comparative study of polar and semipolar (112¯2) InGaN layers grown by metalorganic vapour phase epitaxy

“…[10][11][12] This results here also contradict previous reports on MOVPE-grown ð11 22Þ InGaN. 2,[13][14][15] The different compositions may be due to different growth parameters [13][14][15] or different calculation methods, e.g., with 14,18 and without 13 taking the strain state into account.…”

“…9 It is particularly interesting regarding the application for green and yellow light emitters that an increased indium incorporation on the ð11 22Þ surface was predicted from firstprinciples calculations by Northrup,10 who argued that the strain-repulsive interaction between In-atoms in GaN is weaker on the ð11 22Þ surface than on the nonpolar ð10 10Þ m-plane surface. A higher indium incorporation for semipolar planes than for the basal plane was predicted from two-dimensional modelling of metalorganic vapour phase epitaxy (MOVPE) in a vertical reactor, 11,12 with a distinct maximum indium incorporation for ð11 22Þ InGaN, attributed to a minimum in strain energy. The few reported comparative MOVPE growth studies suggest that semipolar ð11 22Þ have a higher indium incorporation rate than polar and nonpolar planes, 2,13,14 or demonstrate that indium incorporation is virtually independent of the growth plane.…”

A method used to overcome polarization effects in semi-polar structures of nitride light-emitting diodes emitting green radiation

“…According to their results, the highest Indium incorporation necessary to obtain green radiation of longer wavelengths has been recorded for the (1122) GaN orientation, although the (2021) and partly the (2021) orientations also enable reaching InGaN layers of a high Indium mole fractions. Analogous results, i.e., the highest InN mole fraction, have been also determined for the inclination angle 58 • (i.e., for the (1122) orientation) using a simplified theoretical model [15]. The p-n junction built-in electric field has been found to oppose the polarization-related electric field in the quantum wells (QWs) on the (2021)-oriented substrate whereas both the above fields have the same directions within the QWs on the (1122) and the (2021) substrates.…”

Experimental study of the orientation dependence of indium incorporation in GaInN

“…Early work focused on the (10-1-1) GaN substrate orientation as GaInN LEDs and LDs grown on that orientation for emission in the blue and longer wavelengths showed promise [6][7]. Substantial efforts were made to perfect the growth on (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) GaN [8][9][10][11] as indium incorporation was favored on this orientation. However, material quality degradation due to misfit dislocation generation at high indium content [12] shifted the focus to other orientations, since (20)(21) GaN was shown to be capable of incorporating sufficient indium while maintaining the crystalline quality, enabling the demonstration of the first true green GaN based lasers [13].…”

“…have also been proposed [14][15][16]. Northrup [17] attempted to theoretically predict the relative indium incorporation on the (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) and planes. His first-principle calculations indicated that for a clean and indium rich surface indium incorporation is higher on (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) GaN surface than on a surface.…”