Method and device for generating electriferous excitors in quantum well by undoped photo excitation

Abstract

The invention relates to a method and a device for generating electriferous excitors in a quantum well by undoped photo excitation, in particular to a method and a device for generating electriferous excitors. Laser with the energy higher than the forbidden band width of a ZnSe quantum well is used for exciting a zinc selenide well layer in a hetero-structure of zinc selenide / beryllium telluride so as to generate electrons and cavities. The device comprises a low-temperature thermostat, a laser, a spectrometer, and the like, and an optical path which consists of a reflective mirror, a lens and a prism is put in front of the laser, wherein the low-temperature thermostat is put in front of the prism, and the laser turned by the prism can be irradiated into the low-temperature thermostat; the other lens is put in the rear of the prism and can converge radiant light (namely fluorescence PL) of a zinc selenide / beryllium telluride sample in the low-temperature thermostat; and optical fibers and the spectrometer are put at the rear of the lens, wherein the spectrometer is provided with a CCD detector, and both the spectrometer and the CCD detector are connected to a computer so as to automatically complete spectrum detecting duties. The device has simple method, loose experiment condition and no influence on the structural quality of crystals.

Description

technical field [0001] The invention relates to a method and a device for generating charged excitons, in particular to a method and a device for generating charged excitons in a non-doped quantum well by photo-induced excitation. Background technique [0002] Both zinc selenide (ZnSe) and beryllium telluride (BeTe) are important wide bandgap compound semiconductors with strong ionicity and large binding energy. The zinc selenide / beryllium telluride (ZnSe / BeTe) heterostructure composed of the two has good structural quality, low dislocation density and point defects, and the lattice mismatch at the interface is less than 0.5% ZnSe / BeTe BeTe has a type II energy band structure, which makes the excited electrons and holes in the ZnSe layer spatially separated, and can form a two-dimensional electron gas in the ZnSe layer, resulting in the appearance of charged excitons. These characteristics make the ZnSe / BeTe II quantum well (or superlattice) structure a good candidate mater...

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Problems solved by technology

American academic journal "PhysicalReview B" (2002, volume 65, page 115310, "Optical method for the determination of carrier density in modulation-doped quantum wells") discloses a preparation method for generating charged excitons by a structural doping method ( G.V.Astakhov, et al., 65(2002) 115310), but these impurity ions not only affect the structural quality of the crystal, but also cause the deformation of the energy band structure and even affect the quantum well, and also complicate the growth process due to doping In addition, the American academic journal "Physical Review B" (1996, volume 54, page 10609, "Exciton and trion spectral lineshape in the presence of an electron gas in GaAs / AlAs quantum wells") discloses tunneling particle injection method to generate charged excitons (A. Manassen, et al., 54 (1996) 10609), but because the tunneling particle injection is affected by the reflection of the barrier layer and various defects in the barrier layer, the charged excitons The formation efficiency of electrons is affected, and it is also necessary to use two excitation light sources at the same time

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