Thermal stability and temperature dependent electron spin resonance characteristics of the As acceptor in geological 2H-MoS2

Electron spin resonance (ESR) results are presented on the thermal stability and temperature dependence of the ESR spectral characteristics of the As acceptor dopant (As substituting for S site) in geological 2H-MoS2. Under sequential isochronal heating in H-2 (1.1 atm), the As dopant density is found to remain unaffected for anneal temperatures (T(an)s) up to 525 degrees C, above which the density moderately decreases (similar to 3 times) for T-an -> 840 degrees C. In turn, vacuum annealing is seen to result in a gradual increase (2-3 times) of the As acceptor density for T-an increasing from 400 degrees C -> 840 degrees C, pointing to a positive 'regain' of misconfigured As impurities in pristine geo-MoS2. Finally, meticulous monitoring of the ESR signal intensity versus tempertaure at X-band confirms the previously inferred As acceptor activation energy of 0.7 +/- 0.2 meV at K-band. The appropriateness of the latter ESR probing and analysis approach has been consolidated by application to the archetypal case of decoupled P donors in n-Si, resulting in an ESR-determined activation energy (42 +/- 4 meV) well in agreement with the generally accepted one. In light of these findings, As is confirmed as a promising candidate for stable covalently bonded p-type doping of MoS2.