A 69Ga, 115In NQR study of polytypes of GaS,GaSe and InSe

Pulsed Fourier transform NQR spectroscopy has been used to study polytypism in the monochalcogenides GaS, GaSe and InSe at 77 K. The spectrum of GaS was consistent with a major contribution from the β phase but showed evidence of higher polytypes, possibly due to ? or γ type faulting. The GaSe spectrum is simply interpreted as an equal mixture of ? and γ types. The four InSe spectra ($\text{I}\text{=}\text{9}\text{2}$¹¹⁵In), showed a multiplicity of lines. The sharpness of the NQR lines of all spectra suggests the existence of regions with a hitherto overlooked high degree of order.