Effect of oxidation on the thermoelectric properties of PbSe thin films

Abstract

The effect of oxidation at room temperature on the thermoelectric properties of PbSe/KCl (001) thin films prepared by thermal evaporation was investigated. The dependences of the electrical conductivity, the Hall coefficient, charge carrier mobility, and thermopower on the PbSe layer thickness (d ϭ 4-200 nm) were obtained. An inversion of the sign of the dominant carriers from n to p at d ϳ 80 nm was observed under decreasing d. The d dependences of the thermoelectric properties were interpreted, taking into consideration the oxidation processes at the film/air interface within the framework of models considering both n-type and p-type carriers.

Influence of Oxygen Post-Growth Annealing on Optical and Electrical Properties of PbSe Thin Films

“…At the same time, it could also passivate the dislocations and defects, resulting in the reduction of optical phonon scattering. The influence of oxidation on transport properties of monocrystalline PbSe thin film (4 nm to 200 nm) grown on (001) KCl substrate by thermal evaporation was reported by Rogacheva et al 15 The dependence of the carrier concentration at 77 K and RT on annealing times at an annealing temperature of 250°C is plotted in Fig. 5.…”

Room-temperature oxygen sensitization in highly textured, nanocrystalline PbTe films: A mechanistic study

“…7,8 Oxidation annealing is known to incorporate oxygen in the film and sensitize the infrared photoresponse of lead chalcogenide. 5,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Oxygen can introduce gap states which deplete electrons and result in spatial separation of carriers, thus increasing the photogenerated carrier lifetime, and enhancing photoconductivity. Some key findings are: (1) polycrystalline lead chalcogenide films evaporated from stoichiometric bulk are usually n-type due to the poor sticking coefficient of chalcogen atoms and hence chalcogen deficiency.…”

“…Some key findings are: (1) polycrystalline lead chalcogenide films evaporated from stoichiometric bulk are usually n-type due to the poor sticking coefficient of chalcogen atoms and hence chalcogen deficiency. After sensitization, oxygen introduces gap states which can deplete electrons from the conduction band; (2) oxygen-sensitized films exhibit p-type conduction, increased film resistivity and very long photogenerated carrier lifetime; (3) oxygen sensitization is a diffusion-limited process; 17,[20][21][22][23][24] (4) grain boundaries assist in oxygen diffusion, as oxygen sensitization in polycrystalline films occurs over a much shorter time scale compared to their single-crystalline counterparts; [15][16][17] and (5) solutiondeposited PbSe films used in commercial IR detectors often exhibit high sheet resistance (10 5 À10 6 X), but reports on the actual carrier concentrations in these films are scarce.…”

Wireless Activation of Neurons in Brain Slices Using Nanostructured Semiconductor Photoelectrodes

“…The SEM images of the photoelectrodes (Figure 2 b–d) show that a uniform thin film of PbSe nanoparticles was coated on the outside surface of the glass microtips. Earlier measurements show that in PbSe films the majority charge carriers are holes, leading to intrinsic p ‐type nanostructures 12…”