Organic-on-organic semiconductor heterojunctions: building block for the next generation of optoelectronic devices

A novel class of optoelectronic devices utilizing thin films of stable crystalline organic semiconductors layered onto inorganic semiconductor substrates is described. The electrical properties of these devices are determined by the energy barrier at the heterojunction contact between the organic and inorganic materials, and in many ways are similar to those of ideal diffused-junction inorganic semiconductor devices. The organic materials can be layered onto semiconductor substrates without inducing large strains in either material, hence allowing a wide range of material combinations with a similarly broad range of optoelectronic functions to be realized. As examples, high-bandwidth photodetectors and field-effect transistors made using organic/inorganic semiconductor heterojunctions are discussed. Modification of the optical and electronic properties of the organic films by irradiation with energetic electron and ion beams is considered.<>