Excitons into one-axis crystals of zinc phosphide (Zn_{3}P_{2})

Abstract

Theoretical study of excitons spectra is offered in this report as for Zn 3 P 2 crystals. Spectra are got in the zero approach of the theory of perturbations with consideration of both the anisotropy of the dispersion law and the selection rules. The existence of two exciton series was found, which corresponds to two valence bands (hh, lh) and the conductivity band (c). It is noteworthy that anisotropy of the dispersion law plus the existence of crystalline packets (layers) normal to the main optical axis, both will permit the consideration of two-dimensional excitons too. The high temperature displaying of these 2D-exciton effects is not eliminated even into bulk crystals. The calculated values of the binding energies as well as the oscillator's strength for the optical transitions are given for a volume (3D) and for two-dimensional (2D) excitons. The model of energy exciton transitions and four-level scheme of stimulated exciton radiation for receiving laser effect are offered.

Size-Dependent Optical Properties of Luminescent Zn3P2 Quantum Dots

“…Accordingly, a number of potential applications have been suggested and successfully demonstrated. 5−7 In contrast, the efforts on group II−V NCs are rare, although these materials exhibit much larger excitonic radii 8 that can potentially demonstrate pronounced size quantization 9,10 and molar absorptivities comparable to those of group II−VI NCs. 11,12 In particular, bulk Zn 3 P 2 exhibits an absorption coefficient in the order of 10 4 cm −1 , 11,12 carrier diffusion length of 5−10 μm, 13 and a direct bandgap of 1.4−1.5 eV, 9,12 making it a promising candidate for solar cells, 14,15 light-emitting diodes, 16 and lithium ion battery applications.…”

“…Research efforts on semiconductor nanocrystals (NCs) have progressed significantly in recent years owing to their size, shape, and composition-dependent photophysical properties and potential applications in a number of optical technologies. − Specifically, group II–VI NCs have gained noteworthy interest due to their relative ease of synthesis and precise morphological control leading to a basic understanding of photophysics. Accordingly, a number of potential applications have been suggested and successfully demonstrated. − In contrast, the efforts on group II–V NCs are rare, although these materials exhibit much larger excitonic radii that can potentially demonstrate pronounced size quantization , and molar absorptivities comparable to those of group II–VI NCs. , In particular, bulk Zn 3 P 2 exhibits an absorption coefficient in the order of 10 4 cm –1 , , carrier diffusion length of 5–10 μm, and a direct bandgap of 1.4–1.5 eV, , making it a promising candidate for solar cells, , light-emitting diodes, and lithium ion battery applications . Accordingly, Catalano and co-workers demonstrated the use of polycrystalline Zn 3 P 2 in Schottky–Barriers and Zn 3 P 2 /ZnO heterojunction photovoltaic devices with power conversion efficiencies up to ∼6%.…”

Synthesis and electrical characterization of Zn3P2nanowires

“…This result shows the presence of additional levels inside the Zn 3 P 2 bandgap at 49 ± 10 meV [19]. In fact, the electronic band structure of bulk Zn 3 P 2 samples is characterized by zinc vacancy levels which were suggested as the origin of different acceptor levels (0.19 eV and 0.29 eV) [7,33] and by those generated by phosphorous interstitial atoms (from 14 meV to 50 meV) [13]. The 49 meV level when excited (the room temperature is high enough for that) effectively provides the carriers for conduction processes, i.e., the dominant transport mechanism is the thermal activation of carriers.…”

Biomimetic-Inspired Infrared Sensors from Zn3P2 Microwires: Study of Their Photoconductivity and Infrared Spectrum Properties

“…Zn 3 P 2 has an anion sublattice in close proximity to the standard FCC (face centered cubic) packing [40]. Their cations occupy only three quarters of the tetrahedral emptiness among anions [41,42] and the cation sublattices are exactly one-quarter vacant. These vacancies determine some key features of zinc phosphide as the presence of numerous discrete levels inside the band gap.…”