Electron paramagnetic resonance and electron-nuclear double resonance study of the neutral copper acceptor in ZnGeP₂crystals

Abstract

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance have been used to characterize the neutral copper acceptor in ZnGeP 2 crystals. The copper substitutes for zinc and behaves as a conventional acceptor (i.e. the 3d electrons do not play a dominant role). Because of a high degree of compensation from native donors, the copper acceptors in our samples were initially in the nonparamagnetic singly ionized state (Cu − Zn ). The paramagnetic neutral state (Cu 0 Zn ) was observed when the crystals were exposed to 632.8 nm or 1064 nm laser light while being held at a temperature below 50 K. The g matrix of the neutral copper acceptor is axial (g = 2.049 and g ⊥ = 2.030), with the unique principal direction parallel to the tetragonal c axis of the crystal. The hyperfine and nuclear quadrupole matrices also exhibit c-axis symmetry ( A = 87.6 MHz, A ⊥ = 34.8 MHz and P = 0.87 MHz for 63 Cu and A = 93.9 MHz, A ⊥ = 37.3 MHz and P = 0.81 MHz for 65 Cu). Equal hyperfine interactions with the four nearest-neighbour phosphorus ions are well resolved in the c-axis EPR spectrum.

Tricadmium Digermanium Tetraarsenide: A New Crystalline Phase Made with a Double‐Containment Ampoule Method

“…Ternary chalcopyrites are a family of materials with composition I‐III‐VI 2 (A I B III C 2 VI ) or II‐IV‐V 2 (A II B IV C 2 V ) that can be formed as amorphous, polycrystalline, and/or single‐crystal compounds that are often semiconductors. The II‐IV‐V 2 chalcopyrites are analogous to the widely studied III‐V materials (i.e., GaP, GaAs), except that their crystal structure is tetragonally distorted from the cubic III‐V zinc‐blende structure . Numerous applications and important properties have been discovered for chalcopyrite compounds and nonchalcopyrite Cd x Ge y As z compounds including photovoltaics and photoconductivity, semiconductor radiation detection, spintronics, nonlinear optics, superconductivity, high refractive index ( n ) ( n ≥ 3.5), high room temperature electron mobility, and windows for infrared lasers …”