<p>The <i>EK</i> dispersion relation for GaAsNSb/GaAs spherical quantum dots (QDs) under hydrostatic-induced pressure has been investigated through numerical simulation by diagonalizing the modified 16-band kp Hamiltonian matrix. It has been observed that the QDs bandgap increases nonlinearly with hydrostatic pressure for distinct mole fractions of nitrogen (N) % (range 0–3%), with 6% antimony (Sb). An increase in spin–orbit splitting energy causes a crossover at ~ 11% Sb under compressive strain while at ~ 16% N under tensile strain. A decremental effect of radial and tangential strain percentages for distinct dot radii. However, hydrostatic and biaxial strain increase with induced pressure, with a slope of <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$2\times {10}^{-4}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>2</mn> <mo>×</mo> <msup> <mrow> <mn>10</mn> </mrow> <mrow> <mo>-</mo> <mn>4</mn> </mrow> </msup> </mrow> </math></EquationSource> </InlineEquation> per Kbar and <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$7.3\times {10}^{-4}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>7.3</mn> <mo>×</mo> <msup> <mrow> <mn>10</mn> </mrow> <mrow> <mo>-</mo> <mn>4</mn> </mrow> </msup> </mrow> </math></EquationSource> </InlineEquation> per Kbar, respectively. The contact pressure increases with an increasing mole fraction of Sb, while an increasing N concentration tends to reduce the contact pressure slightly. The ground-state binding energy decreases with increasing dot radii due to reduced quantum confinement. A significant redshift for the enhanced carrier concentration & dot radii while a relative blue shift with increasing hydrostatic pressure has been observed in optical gain spectra. Additionally, the onset of the fundamental absorption edge is depicted at an energy of about 0.94 eV for 0 kbar and 1.15 eV at 15 Kbar. These findings are helpful for optoelectronic device applications.</p>

Numerical study of electronic band structure and optical gain of GaAsNSb/GaAs spherical quantum dot under hydrostatic induced pressure using 16 band kp Hamiltonian

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2025年8月29日

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Arvind Sharma,
Sagar Bhattarai,
Kavita Rani Segwal,
Sugandha Gupta,
Abhijit Nayak

摘要

The EK dispersion relation for GaAsNSb/GaAs spherical quantum dots (QDs) under hydrostatic-induced pressure has been investigated through numerical simulation by diagonalizing the modified 16-band kp Hamiltonian matrix. It has been observed that the QDs bandgap increases nonlinearly with hydrostatic pressure for distinct mole fractions of nitrogen (N) % (range 0–3%), with 6% antimony (Sb). An increase in spin–orbit splitting energy causes a crossover at ~ 11% Sb under compressive strain while at ~ 16% N under tensile strain. A decremental effect of radial and tangential strain percentages for distinct dot radii. However, hydrostatic and biaxial strain increase with induced pressure, with a slope of $2\times {10}^{-4}$ $2 \times 10^{- 4}$ per Kbar and $7.3\times {10}^{-4}$ $7.3 \times 10^{- 4}$ per Kbar, respectively. The contact pressure increases with an increasing mole fraction of Sb, while an increasing N concentration tends to reduce the contact pressure slightly. The ground-state binding energy decreases with increasing dot radii due to reduced quantum confinement. A significant redshift for the enhanced carrier concentration & dot radii while a relative blue shift with increasing hydrostatic pressure has been observed in optical gain spectra. Additionally, the onset of the fundamental absorption edge is depicted at an energy of about 0.94 eV for 0 kbar and 1.15 eV at 15 Kbar. These findings are helpful for optoelectronic device applications.