Plot InGaAsP lattice matched InP

Source:

#
#   Copyright (c) 2013-2014, Scott J Maddox
#   Copyright (c) 2025, Duarte Silva
#
#   This file is part of openbandparams.
#
#   openbandparams is free software: you can redistribute it and/or modify
#   it under the terms of the GNU Affero General Public License as published
#   by the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
#   openbandparams is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU Affero General Public License for more details.
#
#   You should have received a copy of the GNU Affero General Public License
#   along with openbandparams.  If not, see <http://www.gnu.org/licenses/>.
#
#############################################################################

import sys
import os
sys.path.insert(0,
    os.path.abspath(os.path.join(os.path.dirname(__file__), '../..')))
import openbandparams as obp
import numpy as np
from matplotlib import pyplot as plt


x=np.linspace(0,1,50)

Eg = 1.35-0.72*x+0.12*x**2

Eg_obp = []
for xi in x:
    mat = obp.GaInPAs(As = xi, a=obp.InP.a())
    Eg_obp.append(mat.Eg())

fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(x, Eg, label='Analytical')
ax.plot(x, Eg_obp, label='OpenBandParams')
ax.set_xlabel('As Composition')
ax.set_ylabel('Bandgap Energy (eV)')
ax.legend()

if __name__ == '__main__':
    import sys
    if len(sys.argv) > 1:
        output_filename = sys.argv[1]
        plt.savefig(output_filename)
    else:
        plt.show()

Result: