ABSTRACT
Abstract. The recent emergence of semiconductors alloys whose fundamental properties are controlled through relatively small compositional changes has opened opportunities for the use of alternative synthesis routes beyond advanced thin-film growth techniques. We present a remarkably simple approach for the synthesis of diluted semiconductors using a combination of ion implantation to introduce the alloying species into a semiconductor host and pulsed-laser melting to regrow the implant-damaged layer into a single-crystalline film. By this process we have formed Gai_xMnxAs epitaxial films that exhibit ferromagnetic Curie temperatures above 130 K. Manganese ion implantation and pulsed-laser melting have been combined to form other ferromagnetic semiconductors including Gai_xMnxP. The availability of a wide range of ions for implantation into numerous semiconductors has enabled us to realize other novel materials including the highly mismatched alloys GaNxAsi_x and ZnOxTei_x. 1
1. Introduction Alloying is a well-established method used to tailor the electrical and optical
properties of semiconductors. Control over the energy band gap of a material, or socalled band gap engineering, via alloy composition lies at the heart of today's most advanced quantum-well devices. For the vast majority of alloy systems, producing the desired changes in properties requires alloying species well beyond several atomic percent and thus requires advanced thin-film deposition techniques. However, recently novel compound semiconductors have emerged whose fundamental properties are dramatically modified through the substitution of a relatively small fraction of host atoms with a very different element. Among these diluted semiconductors are GaNxAsi_x, which exhibits a reduction of the band gap by as much as 180 meV per jc=0.0 1 [1,2], and Gai_xMnxAs, which displays ferromagnetic behavior for x<0.1 [3]. Because such drastic changes in properties result from small changes in composition, constraints in materials synthesis are significantly relaxed making alternative routes available.
