AlInP material model

1. Introduction

This page contains the OghmaNano material model for AlInP (Al(x)In(1-x)P).

Al(x)In(1-x)P ternary alloy

The model is written in Lua and provides simulation-ready material parameterisations for use within OghmaNano. For documentation, licensing, references, and information about the scope and accuracy of these models, see the material scripting documentation.

2. Lua material model

Supporting definitions

-- See end of file for copyright, licensing and documentation links.

local material = {}

-- =====================================================================
-- Al(x)In(1-x)P ternary alloy.
--
-- Composition convention:
--   x = Al fraction   (In fraction = 1 - x)
--   (This is a ternary: state.y is not used.)
--
-- Binary corners:
--   (x=0) -> InP
--   (x=1) -> AlP
--
-- Most properties are linear (Vegard-style) interpolation between the
-- InP and AlP corner values, each evaluated at state.T:
--
--   Q(x) = (1-x) Q_InP + x Q_AlP
--
-- Two properties are treated more carefully:
--   * Eg          -- direct/indirect (Gamma/X) crossover near x~0.37.
--   * thermal cond -- strong alloy-disorder dip mid-composition.
--
-- The central composition is Al(0.52)In(0.48)P (x = 0.52), which is
-- lattice-matched to GaAs. At this composition AlInP is INDIRECT with
-- Eg ~ 2.3 eV, which is exactly why it is used as a transparent
-- wide-gap cladding/window in AlGaInP (red-yellow) LEDs and in
-- GaInP/GaAs solar cells: being indirect and wide-gap, it does not
-- absorb the direct emission of the GaInP active layer.
--
-- NOTE: AlP is not a separate file in this library, so its endpoint
-- values are embedded here (with references in each function).
--
-- FIRST-PASS LIMITATION:
--   * Electron MOBILITY is interpolated linearly and is OPTIMISTIC;
--     alloy-disorder scattering (and X-valley transfer above the
--     crossover) suppress the real mobility (see mu_e).
-- =====================================================================

-- Two-corner linear interpolation helper (v0 at x=0 = InP).

local function lerp(x, v_InP, v_AlP)
	return (1.0 - x)*v_InP + x*v_AlP
end

-- Varshni helper (eV).

local function varshni(T, Eg0, a, b)
	return Eg0 - a*T*T/(T + b)
end

function material.name()
	local enabled = true

	return "AlInP", enabled
end

function material.description()
	local enabled = true

	return "Al(x)In(1-x)P ternary alloy", enabled
end

function material.formula()
	local enabled = true

	return "Al(x)In(1-x)P", enabled
end

function material.Eg(state)
	-- Units: eV
	--
	-- Fundamental band gap of Al(x)In(1-x)P, taken as the minimum of
	-- the Gamma-valley (direct) and X-valley (indirect) gaps. AlInP is
	-- direct for x below ~0.37 and indirect above it.
	--
	-- Method:
	--  1. Interpolate the Gamma gap between InP and AlP (Varshni
	--     endpoints, temperature dependent) with Gamma bowing.
	--  2. Interpolate the X gap similarly with X bowing.
	--  3. Return min(Eg_Gamma, Eg_X).
	--
	-- Parameters from
	-- I. Vurgaftman, J. R. Meyer, L. R. Ram-Mohan,
	-- "Band parameters for III-V compound semiconductors and their
	-- alloys", J. Appl. Phys. 89, 5815-5875, 2001.
	--   InP Gamma: Eg0=1.4236, a=3.63e-4, b=162
	--   AlP Gamma: Eg0=3.63,   a=5.771e-4, b=372
	--   InP X:     Eg0=2.384,  a=3.70e-4, b=147
	--   AlP X:     Eg0=2.52,   a=3.18e-4, b=588
	--   Gamma bowing = -0.48 eV (note: negative -> bows upward)
	--   X bowing     =  0.38 eV
	--
	-- Gives Eg(300 K) = 1.35 eV (x=0, InP, direct), crossover near
	-- x=0.37, ~2.30 eV at x=0.52 (lattice-matched to GaAs, indirect),
	-- and 2.48 eV (x=1, indirect AlP).

	local enabled = true
	local T = state.T
	local x = state.x

	local EgG_InP = varshni(T, 1.4236, 3.63e-4, 162.0)
	local EgG_AlP = varshni(T, 3.63, 5.771e-4, 372.0)
	-- Gamma bowing is -0.48 eV (subtracting a negative bows upward).
	local Eg_Gamma = lerp(x, EgG_InP, EgG_AlP) - (-0.48)*x*(1.0 - x)

	local EgX_InP = varshni(T, 2.384, 3.70e-4, 147.0)
	local EgX_AlP = varshni(T, 2.52, 3.18e-4, 588.0)
	local Eg_X = lerp(x, EgX_InP, EgX_AlP) - 0.38*x*(1.0 - x)

	local value = Eg_Gamma
	if Eg_X < value then
		value = Eg_X
	end

	return value, enabled
end

function material.Xi(state)
	-- Electron affinity
	-- Units: eV
	--
	-- Linear interpolation of the binary corner affinities:
	-- InP 4.38, AlP ~3.98 eV.
	--
	-- Note: the AlP affinity is uncertain. For AlGaInP heterostructures
	-- the band offsets are best set from measured alignments rather
	-- than affinity differencing. Treat as approximate.

	local enabled = true
	local x = state.x

	local value = lerp(x, 4.38, 3.98)

	return value, enabled
end

function material.me(state)
    local enabled = true
    local x = state.x     -- Al fraction, AlxIn1-xP
    -- Gamma mass, InP 0.079 -> AlP 0.22. WARNING: X-indirect for high Al.
    local value = 0.079 + 0.141*x
    return value, enabled
end

function material.mh(state)
    local enabled = true
    local x = state.x
    -- HH[001]: InP 0.53 -> AlP 0.52 (nearly flat)
    local value = 0.53 - 0.01*x
    return value, enabled
end

function material.Nc(state)
	-- Effective conduction-band density of states
	-- Units: m^-3
	--
	-- Linear interpolation of the binary corner values, each with the
	-- (T/300)^1.5 parabolic-band temperature dependence.
	-- Nc(300 K): InP 5.7e23, AlP 1.7e25 m^-3.
	--
	-- Note: Nc rises with x because the multi-valley X minima (heavier,
	-- degenerate) dominate above the crossover; the linear form smooths
	-- this.

	local enabled = true
	local T = state.T
	local x = state.x
	local f = (T/300.0)^1.5

	local value = lerp(x, 5.7e23, 1.7e25)*f

	return value, enabled
end

function material.Nv(state)
	-- Effective valence-band density of states
	-- Units: m^-3
	--
	-- Linear interpolation of the binary corner values, each with the
	-- (T/300)^1.5 temperature dependence.
	-- Nv(300 K): InP 1.1e25, AlP 1.5e25 m^-3.

	local enabled = true
	local T = state.T
	local x = state.x
	local f = (T/300.0)^1.5

	local value = lerp(x, 1.1e25, 1.5e25)*f

	return value, enabled
end

function material.mu_e(state)
	-- Low-field electron mobility
	-- Units: m^2 V^-1 s^-1
	--
	-- Linear interpolation of the binary corner mobilities, each with
	-- its own phonon-limited temperature dependence:
	--   InP 0.54  * (300/T)^2.0
	--   AlP 0.008 * (300/T)^1.8
	--
	-- WARNING: this linear interpolation is OPTIMISTIC. Alloy-disorder
	-- scattering suppresses the real electron mobility, and above the
	-- crossover (x > ~0.37) the heavy X valleys reduce it further.
	-- Measured Al(0.52)In(0.48)P is low (tens of cm^2/V/s to ~100).
	-- Override with a measured mobility for quantitative work.

	local enabled = true
	local T = state.T
	local x = state.x

	local m_InP = 0.54 *(300.0/T)^2.0
	local m_AlP = 0.008*(300.0/T)^1.8

	local value = lerp(x, m_InP, m_AlP)

	return value, enabled
end

function material.mue_x(state)
	return material.mu_e(state)
end

function material.mue_y(state)
	return material.mu_e(state)
end

function material.mue_z(state)
	return material.mu_e(state)
end

function material.mu_h(state)
	-- Low-field hole mobility
	-- Units: m^2 V^-1 s^-1
	--
	-- Linear interpolation of the binary corner mobilities:
	--   InP 0.02  * (300/T)^2.0
	--   AlP 0.010 * (300/T)^1.8
	--
	-- Note: the AlP hole mobility is poorly constrained; alloy
	-- scattering reduces the real value further.

	local enabled = true
	local T = state.T
	local x = state.x

	local m_InP = 0.02 *(300.0/T)^2.0
	local m_AlP = 0.010*(300.0/T)^1.8

	local value = lerp(x, m_InP, m_AlP)

	return value, enabled
end

function material.muh_x(state)
	return material.mu_h(state)
end

function material.muh_y(state)
	return material.mu_h(state)
end

function material.muh_z(state)
	return material.mu_h(state)
end

function material.epsilonr(state)
	-- Relative static permittivity
	-- Dimensionless
	--
	-- Linear interpolation of the binary corner values:
	-- InP 12.5, AlP 9.8.

	local enabled = true
	local x = state.x

	local value = lerp(x, 12.5, 9.8)

	return value, enabled
end

function material.free_to_free_recombination(state)
	-- Radiative (band-to-band) recombination coefficient
	-- Units: m^3 s^-1
	--
	-- Linear interpolation of the binary corner values:
	-- InP 1.2e-16, AlP 1.0e-19.
	--
	-- Note: at the usual (lattice-matched, indirect) AlInP composition,
	-- band-to-band radiative recombination is weak -- consistent with
	-- its transparent-cladding role. Adjust by hand.

	local enabled = true
	local x = state.x

	local value = lerp(x, 1.2e-16, 1.0e-19)

	return value, enabled
end

function material.auger_Cn(state)
	-- Electron Auger recombination coefficient
	-- Units: m^6 s^-1
	--
	-- Linear interpolation of the binary corner values:
	-- InP 9.0e-43, AlP 1.0e-43.
	--
	-- Note: representative placeholders; adjust by hand.

	local enabled = true
	local x = state.x

	local value = lerp(x, 9.0e-43, 1.0e-43)

	return value, enabled
end

function material.auger_Cp(state)
	-- Hole Auger recombination coefficient
	-- Units: m^6 s^-1
	--
	-- Linear interpolation of the binary corner values:
	-- InP 9.0e-43, AlP 1.0e-43.

	local enabled = true
	local x = state.x

	local value = lerp(x, 9.0e-43, 1.0e-43)

	return value, enabled
end

function material.ss_srh_trap_energy(state)
	-- SRH trap energy relative to the middle of the band gap.
	-- Units: eV
	--
	-- Positive values are above mid-gap (towards the conduction band).
	-- Negative values are below mid-gap (towards the valence band).

	local enabled = true
	local value = 0.0

	return value, enabled
end

function material.ss_srh_Nt(state)
	-- SRH trap density
	-- Units: m^-3
	--
	-- Material-quality dependent; set from the intended bulk lifetime.
	-- Representative placeholder for device-grade material.
	--
	-- Note: high-Al phosphides (like high-Al arsenides) are prone to
	-- oxygen-related deep traps and difficult n-type doping; set from
	-- your material.

	local enabled = true
	local value = 1.0e21

	return value, enabled
end

function material.ss_srh_sigma_n(state)
	-- Electron capture cross section
	-- Units: m^2
	--
	-- Representative value ~1e-15 cm^2 = 1e-19 m^2.

	local enabled = true
	local value = 1.0e-19

	return value, enabled
end

function material.ss_srh_sigma_p(state)
	-- Hole capture cross section
	-- Units: m^2
	--
	-- Representative value ~1e-15 cm^2 = 1e-19 m^2.

	local enabled = true
	local value = 1.0e-19

	return value, enabled
end

function material.thermal_kl(state)
	-- Thermal conductivity
	-- Units: W m^-1 K^-1
	--
	-- Alloy thermal conductivity via a thermal-resistivity model
	-- (after S. Adachi): the resistivity W = 1/kappa interpolates
	-- linearly between the binaries PLUS a bimodal alloy-disorder term
	-- that peaks mid-composition:
	--
	--   W(x,T) = (1-x) W_InP(T) + x W_AlP(T) + C_alloy * x(1-x)
	--   kappa  = 1 / W
	--
	-- with C_alloy = 0.62 m*K/W (fitted to reproduce a measured
	-- Al(0.52)In(0.48)P value of ~6 W/m/K), and endpoint conductivities
	-- kappa_InP = 68*(300/T)^1.4 and kappa_AlP = 90*(300/T)^1.4 W/m/K.
	--
	-- Reproduces the strong AlInP conductivity dip (to ~6 W/m/K near
	-- the lattice-matched composition); a linear interpolation would
	-- badly overestimate it.

	local enabled = true
	local T = state.T
	local x = state.x

	local W_InP = 1.0/(68.0*(300.0/T)^1.4)
	local W_AlP = 1.0/(90.0*(300.0/T)^1.4)
	local C_alloy = 0.62

	local W = (1.0 - x)*W_InP + x*W_AlP + C_alloy*x*(1.0 - x)
	local value = 1.0/W

	return value, enabled
end

function material.heat_capacity(state)
	-- Specific heat capacity
	-- Units: J kg^-1 K^-1
	--
	-- Linear interpolation (approximately Neumann-Kopp) of the binary
	-- corner values: InP 310, AlP 730.

	local enabled = true
	local x = state.x

	local value = lerp(x, 310.0, 730.0)

	return value, enabled
end

function material.density(state)
	-- Mass density
	-- Units: kg m^-3
	--
	-- Linear interpolation of the binary corner values:
	-- InP 4810, AlP 2360.

	local enabled = true
	local x = state.x

	local value = lerp(x, 4810.0, 2360.0)

	return value, enabled
end

function material.lattice_constant(state)
	-- Cubic lattice constant
	-- Units: m
	--
	-- Vegard's law between the binary corners, each with its own
	-- linear thermal expansion:
	--   InP a=5.8697 A, exp 4.6e-6 /K
	--   AlP a=5.4672 A, exp 5.3e-6 /K
	-- (Vurgaftman et al., 2001.)
	--
	-- Lattice matching to GaAs (a = 5.65325 A) occurs at x ~ 0.52, i.e.
	-- Al(0.52)In(0.48)P -- the standard transparent cladding/window in
	-- AlGaInP LEDs and GaInP/GaAs solar cells.

	local enabled = true
	local T = state.T
	local x = state.x

	local a_InP = 5.8697e-10*(1.0 + 4.6e-6*(T - 300.0))
	local a_AlP = 5.4672e-10*(1.0 + 5.3e-6*(T - 300.0))

	local value = lerp(x, a_InP, a_AlP)

	return value, enabled
end

function material.thermal_tau_e(state)
	-- Electron energy relaxation time towards the lattice temperature
	-- Units: s
	--
	-- Value basis: III-V family estimate
	-- Confidence: Medium
	--
	-- Reference:
	-- https://www.mdpi.com/2673-3978/3/2/16
	--
	-- Comments:
	-- Representative III-V carrier-to-lattice relaxation time. GaAs-like values
	-- are typically sub-ps to ps and field dependent.

	local enabled = true
	local value = 5.000000e-13

	return value, enabled
end

function material.thermal_tau_h(state)
	-- Hole energy relaxation time towards the lattice temperature
	-- Units: s
	--
	-- Value basis: III-V family estimate
	-- Confidence: Medium
	--
	-- Reference:
	-- https://www.mdpi.com/2673-3978/3/2/16
	--
	-- Comments:
	-- Representative III-V carrier-to-lattice relaxation time. GaAs-like values
	-- are typically sub-ps to ps and field dependent.

	local enabled = true
	local value = 5.000000e-13

	return value, enabled
end

function material.delta_so(state)
	-- Spin-orbit splitting energy (Delta_SO)
	-- Units: eV
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = (x)*0.07 + ((1.0-x))*0.108

	return value, enabled
end

function material.Ep(state)
	-- Kane energy E_P (optical matrix element parameter)
	-- Units: eV
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = (x)*17.7 + ((1.0-x))*20.7

	return value, enabled
end

function material.gamma1(state)
	-- Luttinger parameter gamma1
	-- Units: dimensionless
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = (x)*3.35 + ((1.0-x))*5.08

	return value, enabled
end

function material.gamma2(state)
	-- Luttinger parameter gamma2
	-- Units: dimensionless
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = (x)*0.71 + ((1.0-x))*1.6

	return value, enabled
end

function material.gamma3(state)
	-- Luttinger parameter gamma3
	-- Units: dimensionless
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = (x)*1.23 + ((1.0-x))*2.1

	return value, enabled
end

function material.ac(state)
	-- Conduction-band hydrostatic deformation potential a_c
	-- Units: eV
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- VMR sign convention: interband hydrostatic deformation potential
	-- a_gap = a_c - a_v, with a_c negative and a_v tabulated positive.
	-- Sign preserved from source; no sign flip applied.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = (x)*-5.7 + ((1.0-x))*-6

	return value, enabled
end

function material.av(state)
	-- Valence-band hydrostatic deformation potential a_v
	-- Units: eV
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- VMR sign convention: a_v tabulated as a POSITIVE number; the
	-- interband hydrostatic deformation potential is a_gap = a_c - a_v.
	-- Sign preserved from source; no sign flip applied.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = (x)*3 + ((1.0-x))*1.27

	return value, enabled
end

function material.b(state)
	-- Valence-band shear (tetragonal) deformation potential b
	-- Units: eV
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Sign convention as in VMR (b negative). Sign preserved; not flipped.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = (x)*-1.5 + ((1.0-x))*-2

	return value, enabled
end

function material.d(state)
	-- Valence-band shear (rhombohedral) deformation potential d
	-- Units: eV
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Sign convention as in VMR (d negative). Sign preserved; not flipped.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = (x)*-4.6 + ((1.0-x))*-5

	return value, enabled
end

function material.lattice_a(state)
	-- Cubic (zincblende) lattice constant a
	-- Units: m
	--
	-- Reference:
	-- Vegard's law (linear) interpolation of AlP, InP endpoints,
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Endpoint a(T)=a300+da/dT*(T-300); linear (Vegard) mixing.

	local enabled = true
	local x = state.x
	local T = state.T
	local value = ((x)*(5.4672 + 2.92e-05*(T-300.0)) + ((1.0-x))*(5.8697 + 2.79e-05*(T-300.0)))*1e-10

	return value, enabled
end

function material.C11(state)
	-- Elastic stiffness constant C11
	-- Units: Pa
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = ((x)*133 + ((1.0-x))*101.1)*1e9

	return value, enabled
end

function material.C12(state)
	-- Elastic stiffness constant C12
	-- Units: Pa
	--
	-- Reference:
	-- Linear interpolation of binary endpoints AlP, InP from
	-- Vurgaftman, Meyer, Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).
	--
	-- Note:
	-- Composition: Al(x)In(1-x)P; x = Al mole fraction.
	-- Linear interpolation of endpoints (no bowing applied).

	local enabled = true
	local x = state.x
	local value = ((x)*63 + ((1.0-x))*56.1)*1e9

	return value, enabled
end

function material.C44(state)
    -- Elastic stiffness constant C44
    -- Units: Pa
    --
    -- Composition: Al_x In_(1-x) P, x = state.x (first-listed cation carries
    -- x, as for AlGaAs/AlInAs; check against the existing file's convention).
    --
    -- Reference (both endpoints):
    -- I. Vurgaftman, J. R. Meyer, L. R. Ram-Mohan,
    -- "Band parameters for III-V compound semiconductors and their alloys,"
    -- J. Appl. Phys. 89, 5815 (2001), recommended binary parameter tables
    -- (Tables I-VI checked for GaAs, AlAs, InAs, GaP, AlP, InP).
    -- DOI: 10.1063/1.1368156
    --
    -- Notes:
    -- Recommended binary values: AlP C44 = 615 kbar = 61.5 GPa,
    -- InP C44 = 456 kbar = 45.6 GPa (1 kbar = 1e8 Pa).
    -- The AlP elastic constants in the compilation are themselves largely
    -- theory-based (no reliable bulk ultrasonic data); treat the Al-rich end
    -- as approximate.
    --
    -- Interpolation:
    -- Linear in state.x: C44(x) = (1-x)*C44_InP + x*C44_AlP. No bowing.

    local enabled = true
    local x = state.x

    local InP = 45.6e9
    local AlP = 61.5e9

    local value = (1.0-x)*InP + x*AlP

    return value, enabled
end

function material.phonon_lo_energy(state)
    -- Representative LO phonon energy for polar optical (Frohlich) scattering
    -- Units: eV
    --
    -- No sufficiently reliable value/reference identified.
    -- Disabled rather than estimated.
    --
    -- Notes:
    -- The AlP endpoint dielectric and piezoelectric data (sparse bulk
    -- data on a hygroscopic material) could not be verified against a primary
    -- source, so no Al_x In_(1-x) P interpolation is implemented for this
    -- parameter.
    -- AlInP is a two-mode (InP-like / AlP-like) alloy; no composition-
    -- dependent effective one-mode Frohlich energy with a primary reference
    -- was found.

    local enabled = false
    local value = 0.0

    return value, enabled
end

function material.epsilon_static(state)
    -- Static relative dielectric constant (lattice + electronic)
    -- Dimensionless
    --
    -- No sufficiently reliable value/reference identified.
    -- Disabled rather than estimated.
    --
    -- Notes:
    -- The AlP endpoint dielectric and piezoelectric data (sparse bulk
    -- data on a hygroscopic material) could not be verified against a primary
    -- source, so no Al_x In_(1-x) P interpolation is implemented for this
    -- parameter.

    local enabled = false
    local value = 0.0

    return value, enabled
end

function material.epsilon_inf(state)
    -- High-frequency (electronic) relative dielectric constant
    -- Dimensionless
    --
    -- No sufficiently reliable value/reference identified.
    -- Disabled rather than estimated.
    --
    -- Notes:
    -- The AlP endpoint dielectric and piezoelectric data (sparse bulk
    -- data on a hygroscopic material) could not be verified against a primary
    -- source, so no Al_x In_(1-x) P interpolation is implemented for this
    -- parameter.

    local enabled = false
    local value = 0.0

    return value, enabled
end

function material.e14(state)
    -- Zincblende piezoelectric stress coefficient e14
    -- Units: C m^-2
    --
    -- No sufficiently reliable value/reference identified.
    -- Disabled rather than estimated.
    --
    -- Notes:
    -- The AlP endpoint dielectric and piezoelectric data (sparse bulk
    -- data on a hygroscopic material) could not be verified against a primary
    -- source, so no Al_x In_(1-x) P interpolation is implemented for this
    -- parameter.

    local enabled = false
    local value = 0.0

    return value, enabled
end

function material.print()
	-- Representative composition: Al(0.52)In(0.48)P, lattice-matched to
	-- GaAs (x = Al fraction = 0.52); indirect, ~2.3 eV.
	local state = {
		T = 300.0,
		x = 0.52,
		y = 0.0,
		z = 0.0,
		photon_density = 0.0,
	}

	print(string.format("Material:               %s", material.name()))
	print(string.format("Description:            %s", material.description()))
	print(string.format("Formula:                %s", material.formula()))
	print(string.format("Temperature:            %.2f K", state.T))
	print(string.format("Composition x (Al):     %.4f", state.x))
	print(string.format("Position:               %.6e, %.6e, %.6e m", state.x, state.y, state.z))
	print(string.format("Photon density:         %.6e m^-3", state.photon_density))

	print(string.format("Band gap:               %.6f eV", material.Eg(state)))
	print(string.format("Electron affinity:      %.6f eV", material.Xi(state)))
	print(string.format("Electron mobility:      %.6e m^2/V/s", material.mu_e(state)))
	print(string.format("Hole mobility:          %.6e m^2/V/s", material.mu_h(state)))
	print(string.format("Nc:                     %.6e m^-3", material.Nc(state)))
	print(string.format("Nv:                     %.6e m^-3", material.Nv(state)))
	print(string.format("Relative permittivity:  %.6f", material.epsilonr(state)))

	print(string.format("Radiative coeff.:       %.6e m^3/s", material.free_to_free_recombination(state)))
	print(string.format("Electron Auger coeff.:  %.6e m^6/s", material.auger_Cn(state)))
	print(string.format("Hole Auger coeff.:      %.6e m^6/s", material.auger_Cp(state)))

	print(string.format("SRH trap energy:        %.6f eV", material.ss_srh_trap_energy(state)))
	print(string.format("SRH trap density:       %.6e m^-3", material.ss_srh_Nt(state)))
	print(string.format("SRH sigma n:            %.6e m^2", material.ss_srh_sigma_n(state)))
	print(string.format("SRH sigma p:            %.6e m^2", material.ss_srh_sigma_p(state)))

	print(string.format("Electron energy relax.:  %.6e s", material.thermal_tau_e(state)))
	print(string.format("Hole energy relax.:      %.6e s", material.thermal_tau_h(state)))

	print(string.format("Thermal conductivity:   %.6e W/m/K", material.thermal_kl(state)))
	print(string.format("Heat capacity:          %.6e J/kg/K", material.heat_capacity(state)))
	print(string.format("Mass density:           %.6e kg/m^3", material.density(state)))
end

return material

-- ============================================================================
-- Copyright (C) 2026 The OghmaNano Project
-- All rights reserved.
--
-- This file is part of the OghmaNano Materials Model Library.
--
-- Website:
-- https://www.oghma-nano.com
--
-- Documentation and accuracy statement:
-- https://www.oghma-nano.com/manual/material-scripts.html
--
-- These material models are provided to support scientific research and
-- semiconductor device simulation. If you find them useful, please cite
-- OghmaNano where appropriate. Please do not redistribute these files or
-- incorporate them into other software or databases without permission.
-- ============================================================================