PbTe Flash Evaporation on Si <100> Substrates for Heterojunction Infrared Detectors

Abstract

This work is to present results of flash evaporation of PbTe directly over single crystals p-type Si substrates, in order to produce heterojunction infrared detectors (HIRD), working at 4.3.tm IR wavelength. The evaporation was performed on modified JEOL vacuum equipment, model JEE4B(a), working with vacuum pressure around 10-5 torr, using diffusion pump. The HIRDs produced with this method presented the same detectivity (D*) values of HIRDs made with Hot Wall Epitaxial System (HWE)(b), in which PbTe epitaxial layers were grown directly over the same Si substrates, where an ionic pump reached about 10-torr as vacuum pressure. The best results, were obtained with PbTe layers grown with Molecular Beam Epitaxial (MBE) method(c) directly over Si substrates, where the vacuum pressure is around 10-9 torr, also using an ionic pump. The advantage of growing PbTe directly over Si wafers is that the HIRDs perform at room temperature.

PbTe Nanowires Electrochemically Deposited on Si Substrates as PbTe/Si Heterojunction Infrared Photodetectors

“…Sahay and Guruswamy 22 substrates. Guimaraẽs et al 23 used molecular beam epitaxy and flash evaporation to epitaxy PbTe materials on Si substrates to form heterostructure detectors, and the detectivity of the detectors prepared by the two methods was 6.7 × 10 6 cm Hz 1/2 W −1 and 4.8 × 10 5 cm Hz 1/2 W −1 under laser irradiation at 4.3 μm, respectively. In summary, some studies have confirmed the feasibility of heterogeneous growth of high-quality lead telluride materials on a silicon surface.…”

“…Due to the approximate lattice spacing in the (200) PbTe and (111) Si directions, PbTe films can be epitaxially grown on (111) Si substrates. Guimarães et al used molecular beam epitaxy and flash evaporation to epitaxy PbTe materials on Si substrates to form heterostructure detectors, and the detectivity of the detectors prepared by the two methods was 6.7 × 10 6 cm Hz 1/2 W –1 and 4.8 × 10 5 cm Hz 1/2 W –1 under laser irradiation at 4.3 μm, respectively.…”