{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "import matplotlib.pyplot as plt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "from solcore import si, material\n",
    "from solcore.structure import Junction, Layer\n",
    "from solcore.solar_cell import SolarCell\n",
    "from solcore.solar_cell_solver import solar_cell_solver, default_options\n",
    "from solcore.light_source import LightSource\n",
    "from solcore.constants import vacuum_permittivity\n",
    "from solcore.optics import RCWASolverError"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "user options"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "T = 298\n",
    "wl = si(np.linspace(400, 900, 80), 'nm')\n",
    "light_source = LightSource(source_type='standard', version='AM1.5g', x=wl,\n",
    "                           output_units='photon_flux_per_m', concentration=1)\n",
    "opts = default_options\n",
    "opts.wavelength, opts.no_back_reflection, opts.size, opts.light_source, opts.T_ambient = \\\n",
    "    wl, False, [400, 400], light_source, T\n",
    "opts.recalculate_absorption = True\n",
    "# The size of the unit cell for the RCWA structure is 400 x 400 nm"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Defining all the materials we need"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "Air = material('Air')(T=T)\n",
    "p_GaAs = material('GaAs')(T=T, Na=si('4e18cm-3'))  # for the GaAs cell emitter\n",
    "n_GaAs = material('GaAs')(T=T, Nd=si('2e17cm-3'))  # for the GaAs cell base\n",
    "AlAs, GaAs = material('AlAs')(T=T), material('GaAs')(T=T)  # for the DBR\n",
    "SiO2 = material('SiO2', sopra=True)(T=T)  # for the spacer layer\n",
    "TiO2 = material('TiO2', sopra=True)(T=T)  # for the nanoparticles"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "some parameters for the QE solver"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for mat in [n_GaAs, p_GaAs]:\n",
    "    mat.hole_mobility, mat.electron_mobility, mat.permittivity = 3.4e-3, 5e-2, 9 * vacuum_permittivity\n",
    "    n_GaAs.hole_diffusion_length, p_GaAs.electron_diffusion_length = si(\"500nm\"), si(\"5um\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Define the different parts of the structure we will use. For the GaAs junction, we use the depletion approximation"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "GaAs_junction = [Junction([Layer(width=si('100nm'), material=p_GaAs, role=\"emitter\"),\n",
    "                           Layer(width=si('400nm'), material=n_GaAs, role=\"base\")], T=T, kind='DA')]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "this creates 10 repetitions of the AlAs and GaAs layers, to make the DBR structure"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "DBR = 10 * [Layer(width=si(\"73nm\"), material=AlAs), Layer(width=si(\"60nm\"), material=GaAs)]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The layer with nanoparticles"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "NP_layer = [Layer(si('50nm'), Air, geometry=[{'type': 'circle', 'mat': TiO2, 'center': (200, 200),\n",
    "                                              'radius': 50}])]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "substrate = [Layer(width=si('50um'), material=GaAs)]\n",
    "spacer = [Layer(width=si('25nm'), material=SiO2)]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "--------------------------------------------------------------------------<br>\n",
    "solar cell with SiO2 coating"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "solar_cell = SolarCell(spacer + GaAs_junction + substrate)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "opts.optics_method = 'TMM'\n",
    "solar_cell_solver(solar_cell, 'qe', opts)\n",
    "TMM_EQE = solar_cell[1].eqe(opts.wavelength)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "opts.optics_method = 'BL'\n",
    "solar_cell_solver(solar_cell, 'qe', opts)\n",
    "BL_EQE = solar_cell[1].eqe(opts.wavelength)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "--------------------------------------------------------------------------<br>\n",
    "as above, with a DBR on the back"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "solar_cell = SolarCell(spacer + GaAs_junction + DBR + substrate)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "opts.optics_method = 'TMM'\n",
    "solar_cell_solver(solar_cell, 'qe', opts)\n",
    "TMM_EQE_DBR = solar_cell[1].eqe(opts.wavelength)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "--------------------------------------------------------------------------<br>\n",
    "cell with TiO2 nanocylinder array on the front"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "solar_cell = SolarCell(NP_layer + spacer + GaAs_junction + DBR + substrate)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "opts.optics_method = 'TMM'\n",
    "solar_cell_solver(solar_cell, 'qe', opts)\n",
    "TMM_EQE_NP = solar_cell[2].eqe(opts.wavelength)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "opts.optics_method = 'BL'\n",
    "solar_cell_solver(solar_cell, 'qe', opts)\n",
    "BL_EQE_NP = solar_cell[2].eqe(opts.wavelength)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "try:\n",
    "    opts.optics_method = 'RCWA'\n",
    "    opts.orders = 49  # number of diffraction orders to keep in the RCWA solver\n",
    "    solar_cell_solver(solar_cell, 'qe', opts)\n",
    "    RCWA_EQE_NP = solar_cell[2].eqe(opts.wavelength)\n",
    "    RCWA_legend = 'RCWA (GaAs SC + NP array + DBR)'\n",
    "except RCWASolverError:\n",
    "    RCWA_EQE_NP = np.zeros_like(BL_EQE_NP)\n",
    "    RCWA_legend = '(RCWA solver S4 not available)'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "plt.figure()\n",
    "plt.plot(wl * 1e9, BL_EQE_NP, wl * 1e9, TMM_EQE, wl * 1e9, TMM_EQE_DBR, wl * 1e9, RCWA_EQE_NP)\n",
    "plt.legend(labels=['Beer-Lambert law (all structures)', 'TMM (GaAs SC)', 'TMM (GaAs SC + DBR)',\n",
    "                   RCWA_legend])\n",
    "plt.xlabel(\"Wavelength (nm)\")\n",
    "plt.ylabel(\"Quantum efficiency\")\n",
    "plt.show()"
   ]
  }
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