Optoelectronic cleanroom services include work with AlGalnN semiconductor materials. Some preforms are also used in diodes, rectifiers, optoelectronic devices and components packaging. Technetium-99 has also been proposed for optoelectronic devices and nanoscale nuclear batteries. Planar Systems, Inc. is a subsidiary of Shenzhen, China-based Leyard Optoelectronic Co. since 2015. Planar was purchased by Leyard Optoelectronic Co. of China in 2015 for $157 million. It is a dopant in some types of glass in lasers and other optoelectronic devices. Results suggest that trilayer MoS phosphorene is a promising candidate in flexible optoelectronic devices. This is promising for optoelectronic and nanophotonic devices. AU Optronics (AUO; ) is a company in Taiwan that specialises in optoelectronic solutions. The term ""electro-optic"" is often erroneously used as a synonym for ""optoelectronic"". In March 2009, Thorlabs acquired optoelectronic components manufacturer Covega from Gemfire. Tensions and impurities due to low crystal quality result in low optoelectronic properties. For example, this is a common problem for many optoelectronic components. They use a chilled mirror and optoelectronic mechanism to detect condensation on the mirror's surface. The London-based "USH" was founded after the war to manufacture optoelectronic instruments.