Heteroepitaxy of Cd-Rich Ca_xCd_1-xF₂Alloy on Si Substrates and Its Application to Resonant Tunneling Diodes

Growth of ultra-thin fluoride heterostructures on Ge(1 1 1) for quantum devices

“…Growth temperature for the top two layers (200 1C) was identical for the two structures. The temperature of 200 1C is generally too high to obtain good CdF 2 layers for conventional structure grown on Si [4]. Fig.…”

“…However, the fluoride quantum well structures on Si substrates currently face with the serious issue on unstable operation and poor reproducibility due to the chemical reaction between the CdF 2 quantum well layer and Si substrate, especially at relatively high growth temperatures [4].…”

Growth characteristics of ultra-thin epitaxial Ca Mg1−F2 alloys on Si(1 1 1) substrates

“…It is expected that the formation of an alloy with another fluoride material having a smaller lattice constant will be effective in reducing the lattice mismatch. One such candidate is CdF 2 , the alloy of which, Ca x Cd 1Àx F 2 , has already been investigated as a quantum well layer for RTDs [7,8]. However, the Ca x Cd 1Àx F 2 alloy is not suitable for the first layer, which is directly grown on the Si surface as a barrier for the RTDs.…”

“…However, the Ca x Cd 1Àx F 2 alloy is not suitable for the first layer, which is directly grown on the Si surface as a barrier for the RTDs. This is due to a direct chemical reaction between the CdF 2 molecular beam and the Si substrate leading to the dissociation of fluorides [7,9], and can be expressed as…”

Surface modification of Si substrates by CdF2 molecular beam for stable growth of fluoride ultra-thin heterostructures

“…It is known that the CdF 2 molecular beam have large activity for chemical reaction with Si at low temperature [6], such as Si þ 2CdF 2 ! 2Cd þ SiF 4 " :…”