Real-time monitoring of organic vapor-phase deposition of molecular thin films using high-pressure reflection high-energy electron diffraction

The crystalline thin film growth of the organic material, copper phthalocyanine (CuPc), by organic vapor-phase deposition (OVPD) is studied using high-pressure reflection high-energy electron diffraction (HP-RHEED). In situ growth of this material was monitored, in real time, on both highly oriented pyrolytic graphite and native Si O2 on Si(100) substrates. The growth of the first several monolayers on both substrates was found to be independent of the growth conditions; however, the crystalline texture of thicker films was controlled through changes in the substrate temperature and deposition rate. Higher substrate temperatures lead to an increase in crystalline ordering for growth on both substrates. This work shows that HP-RHEED is a powerful tool for real-time monitoring of growth morphology in the low-vacuum OVPD environment, ultimately leading to in situ control of thin film crystalline order.