Photoluminescence study of deep levels in Cr-doped ZnSe

Abstract

Single crystals of intrinsic ZnSe were grown by the seeded physical vapor transport method and the diffusion doping was utilized to incorporate Cr in these crystals. The radiative recombinations in these samples with Cr concentration in the range 1.0–10.2×1019 cm−3 were studied by the steady state photoluminescence technique. It was found that the Cr deep centers inhibit the band-to-band emission in Cr-doped ZnSe. Except in undoped single crystals, no emission corresponding to the band-to-band transition was observed from any of the doped samples. Instead, the higher wavelength emissions associated with Cr deep levels were obtained. This capture of photoexcited carriers by deep centers was verified using different excitation wavelengths. The role of chromium impurities in nonradiative recombination processes was also evidenced from the sharp decreases in the deep level emission intensity with increasing Cr concentration.

Voltammetric Study of Selenium and Two-Stage Electrodeposition of Photoelectrochemically Active Zinc Selenide Semiconductor Films in Ionic Liquid Zinc Chloride-1-Ethyl-3-Methylimidazolium Chloride

“…The two-stage approach guaranteed the formation of stoichiometric ZnSe. SeCl 4 and SeO 2 can be used as the source of Se(IV), with SeO 2 being less expensive. When the deposition was carried out at a potential at which Se(−II) was produced, no Zn was observed in the resulting deposits because Se(IV) + 2Se(−II) → 3Se is a faster reaction than Zn(II) + Se(−II) → ZnSe.…”

“…1 ZnSe has been reported to be a useful material for various optoelectronic devices, such as lightemitting devices, window layers for solar cells, photovoltaic cells, laser screens, film transistors, photoelectrochemical cells, and optical components for infrared lasers. [2][3][4][5][6][7][8][9] Various approaches have been developed for the preparation of ZnSe thin films, including vacuum evaporation, 10,11 chemical bath deposition, 12,13 spray pyrolysis, 14,15 pulsed-laser deposition, 16 chemical vapor deposition, [17][18][19] molecular beam epitaxy, [20][21][22] atomic layer epitaxy, 23 sputtering, 24 and metalorganic chemical vapor deposition. 19,25 Compared with these approaches, electrodeposition is more attractive [26][27][28][29] in terms of convenience, cost, and suitability for the large-scale production of thin films.…”

Spin dependent and nonlinear effects in ZnCrSe and ZnCrTe

“…1+ charge state is located close to midgap positions of ZnSe and ZnTe [3]. Efficient energy up-conversion [4] and also efficient laser emission in infrared [5][6][7] are related to possibility of optical pumping via Cr photo-ionization bands [8], i.e., midgap position of 1+ charge state is crucial for possible practical applications of Cr doped ZnSe and ZnTe.…”

Development of AIIBVI Semiconductors Doped with Cr for IRLaser Application

“…All samples were cut from one as-grown ZnSe single crystal and then mechanically polished so that they have the shape of wafers with dimensions about 5x5xl mm 3 . CdSe crystals were grown by the Czochralski technique.…”

“…Efficient room temperature lasing has been demonstrated with Cr÷+ active ions doped into I-VI chalcogenides such as ZnSe and CdSe [1,2]. Transition metals incorporated into Zn(Cd)Se substitute metallic atoms and create deep levels in the band gap [3]. Only one strong emission at 2.67 eV is observed in the spectrum of the undoped ZnSe, which corresponds to the room temperature band gap energy in ZnSe.…”