ZnSnN2

Contents

• Crystal Structures

• Synthesis and Growth Methods

• Electronic band structure

• Vibrational Properties

• Elastic Properties

• Dielectric Properties

• Index of Refraction

• Non-Linear Optical Coefficients

Crystal Structures:

Spacegroup: Pna2₁ (or Pnb2₁ with current axes choice).

(NOTE: For crystal modeling purposes, select the spacegroup as Pbn2₁ )

Point group: C_2v

Lattice constants:

Wyckoff positions:

Reference [3]

Synthesis and Growth

• • MBE Feldberg et al. [9] (2012)

  • RF-sputter deposition Coronel et al. [10] (2012)

  • VLS growth [1] Quayle et al. (2013)

  • RF-sputtering Fioretti et al. [11] (2015)

Electronic band structure

The band gap is direct at Gamma.

Band gap: 2.02 eV [2] Calc. QSGW, 0.8Sigma + zero point motion correction + exciton binding energy at LDA lattice constant

1.8 eV [4] Calc. QSGW, 0.8Sigma + zero point motion correction + exciton binding energy at Expt. lattice constant of [1]

0.55 eV [2] Calc. LDA

1.70 eV [1] Expt. photoluminescence excitation spectroscopy (PLE)

1.42 eV [5] Calc. Hybrid functional HSE

1.9-2.2 eV [5] Expt. absorption (possibly overestimated by Moss-Burstein)

2.09 eV [6] Calc. PBE0 for Pna2_1 structure

1.12 eV [6] Calc. PBE0 for fully disordered structure

2.12-2.38 eV [6] Optical absorption (possibly overestimated by Moss-Burstein)

Effective masses[2]: conduction band minimum m_cx=0.16, m_cy=0.15, m_cz=0.12

valence band maximum splittings and effective masses

Figure 1: Band structure of ZnSnN₂ in Pna2₁ structure [2].

Figure 2: Band structure of ZnSnN₂ near valence band maximum.[3]

Figure 3: Density of states and partial density of states of ZnSnN₂. [3]

Vibrational properties

There are 12 modes of a₂, 11 of a₁, b₁ and b₂ symmetry.

All modes are Raman active. The a₁, b₁, b₂ are IR active and exhibit LO-TO splitting.

The Raman tensors for a₁ have xx, yy, zz components, for a₂, xy, for b₁ xz and for b₂ yz components

with x||a, y||b, z||c.

a₁ is IR active for z polarization E||c

b₁ is IR active for x polarization E||a

b₂ is IR active for y polarization E||b

Reference: [7]

Predicted Raman and IR spectra can be found in ref. [7] as well as phonon band structure and density of states.

Measured Raman for disordered ZnSnN₂ can be found in Ref. [2]

Born effective charges

Reference [7]

Elastic Properties

Bulk moduli and pressure derivative:

Stiffness and compliance: