A study on matrix assisted pulsed evaporation (MAPLE) of organic materials

Abstract

Organic films can be produced either by MAPLE or directly by PLD (Pulsed laser deposition). For a reasonable deposition rate of ng/cm 2 per pulse for film production by MAPLE a fluence of 1-1.5 J/cm 2 is required at the laser wavelength of 355 nm, while the fluence can be considerably lower at 248 nm. At high fluence the deposition rate of proteins by MAPLE seems to decrease. The surface roughness is still an issue, but at low fluence it seems to be acceptable. The fragmentation rate increases with fluence, and seems to be less pronounced for MAPLE than for PLD. Also this issue is not yet resolved.

Octahydroacridine thin films grown by matrix-assisted pulsed laser evaporation for non linear optical applications

“…In our MAPLE experiments we used a 1% solution of laboratory synthesized OHA [24,30], carefully frozen in liquid nitrogen in a copper target holder [36][37][38][39]. The target holder was kept solid throughout thin film growth procedures.…”

“…The target holder was kept solid throughout thin film growth procedures. From our previous experience and based on literature studies [34][35][36][37][38][39][40], the laser fluence was chosen in the range of 0.1-1 J/cm 2 (Nd:YAG, "Surelite II" p u l s e dl a s e rs y s t e mf r o mC o n t i n u u m Company: 266nm wavelength, 7ns duration of the pulse, 10 Hz), using a 2 mm² spot. All depositions took place in vacuum (1 Â 10 -4 mbar), with the chamber being continuously pumped by a "Pfeiffer-Balzers 4 TPU 170" turbomolecular system (170 l s À 1 volume flow rate).…”