PbSe

PbSe is lead selenide, a binary inorganic compound in the lead chalcogenide family. It crystallizes in the rock-salt (NaCl-type) structure at room temperature and forms as brittle, pale gray crystals.

It has a narrow direct bandgap of about 0.27 eV at room temperature, with the conduction band minimum and valence band maximum located near the L point of the Brillouin zone. The bandgap decreases with increasing temperature. It absorbs strongly in the infrared, with a cutoff near 4–5 μm.

Bulk PbSe can be grown by techniques such as the Bridgman or Czochralski methods; nano-sized crystallites and quantum dots can be prepared by solution-based routes and colloidal synthesis; epitaxial thin films can be grown by molecular beam epitaxy or chemical vapor deposition.

Due to its infrared absorption and tunable bandgap, PbSe is used in infrared photodetectors and focal plane arrays, and is studied for thermoelectric materials and optoelectronic devices. Alloying with tin or sulfur allows tuning of the effective bandgap and lattice properties.

As a lead-containing compound, PbSe is toxic if ingested or inhaled as dust; handling requires appropriate safety measures. The material can oxidize on exposure to air, forming surface films of lead oxides and selenium oxides.