Controlled nitrogen incorporation in GaNSb alloys

Abstract

The incorporation of N in molecular-beam epitaxy of GaNxSb1−x alloys with x ⩽ 0.022 has been investigated as a function of temperature (325–400°C) and growth rate 0.25–1.6 μmh−1. At fixed growth rate, the incorporated N fraction increases as the temperature is reduced until a maximum N content for the particular growth rate reached. At each temperature, there is a range of growth rates over which the N content is inversely proportional to the growth rate; the results are understood in terms of a kinetic model. The systematic growth rate- and temperature-dependence enables the N content and resulting band gap to be controlled

Growth and properties of GaSbBi alloys

“…The Bi content increases as the growth temperature decreases and reaches a plateau corresponding to x ¼ 0.05 for growth temperatures below approximately 275 C. The temperature dependence of the Bi incorporation in GaSb 1Àx Bi x has been modeled using the kinetic approach described by Wood et al 12 and Pan et al 13 that has previously been applied to N incorporation in Ga(In)N x Sb 1Àx alloys. 3,14 The curve shown in Fig. 1 corresponds to an energy barrier for Bi desorption of 1.75 eV and a characteristic surface residence lifetime of Bi atoms of 6.5 ls, compared with the previously reported values for GaNSb of 2.0 eV for the barrier for N desorption and 5 ls for the characteristic surface residence lifetime of N atoms.…”

“…1 corresponds to an energy barrier for Bi desorption of 1.75 eV and a characteristic surface residence lifetime of Bi atoms of 6.5 ls, compared with the previously reported values for GaNSb of 2.0 eV for the barrier for N desorption and 5 ls for the characteristic surface residence lifetime of N atoms. 14 Channeling RBS measurements along the h100i, h110i, and h111i directions indicate that the films have very high epitaxial quality with greater than 98% of the Bi atoms in the substitutional group V sublattice in all films.…”

Increased p-type conductivity in GaNxSb1−x, experimental and theoretical aspects

“…2 The N contents of the relaxed films were determined from x-ray diffraction reciprocal space mapping to vary from 0.18% to 1.31%. The films in the second set were grown to thicknesses in the range 0.33 to 0.40 lm pseudomorphically on GaSb (001) substrates at the University of Warwick with N contents from x-ray diffraction of 0.56% to 2.32%, varied by altering the growth rate at a fixed growth temperature of 320 C. 11,24 The optical properties of these samples are reported in Ref. 20.…”

“…By substituting the group V-atom with low concentrations of nitrogen, large band gap reductions corresponding to wavelengths in the long or very long-wavelength infrared ranges have been reported. [1][2][3][4][5][6][7][8][9][10][11][12] The strong modification of the conduction band when dilute amounts of the host anion of the compound semiconductor is replaced is thought to be caused by N-induced states lying near to the conduction band minimum. [13][14][15][16][17][18][19][20][21] For the alloy GaN x Sb 1Àx , the band gap red shift is especially large.…”

Optical absorption by dilute GaNSb alloys: Influence of N pair states

“…6 The second set was grown to a thickness of 0.4 lm on GaSb(001) substrates at the University of Warwick with N contents determined from x-ray diffraction of 0.55 to 2.49%, varied by altering the growth rate at a fixed growth temperature of 320 C. 1,7 Reflectance and transmittance measurements were performed at room temperature using a Bruker Vertex 70 V Fourier-transform infrared spectrometer, using a liquid nitrogen-cooled mercury cadmium telluride detector with a working range between 0.05 and 1.2 eV. The absorption coefficient, a, was calculated using the equation…”