TY - JOUR
T1 - Fine tuning of the emission of ultra-thin quantum wells of CdSe and CdTe by modification of the growth temperature
AU - Hernández-Calderón, I.
AU - Salcedo-Reyes, J. C.
AU - Alfaro-Martínez, A.
AU - García-Rocha, M.
N1 - Funding Information:
This work was partially supported by Conacyt. JCSR and AAM are indebted to Conacyt-Mexico for a fellowship during the development of this research. We thank the expert technical assistance of Zacarias Rivera, Angel Guillén and Héctor Silva.
PY - 2005/11
Y1 - 2005/11
N2 - Ultra-thin quantum wells (UTQWs) of CdTe and CdSe should present a emission energy as a function of thickness, however, we have observed that depending on substrate temperature the peak energy is modified: the higher the growth temperature the larger the blue shift. Considering (i) a chemical interaction that produces the substitution of Cd atoms by Zn atoms at the QW-barrier interface, and, (ii) the large Bohr radius of the excitons in II-VI semiconductors, we argue that a few percent substitution of Cd atoms by Zn atoms is perceived as a change in average composition and not as a thickness fluctuation. Since the Cd substitution is a thermally activated process, a larger blue shift is expected at the higher temperatures. Therefore, the UTQWs can be described as made of Zn1-xCdxSe or Zn 1-xCdxTe alloys with high Cd content, x∼1 at the lower substrate temperatures (Ts). Then, the proper selection of T s can be advantageously employed for fine tuning of the excitonic emission in the energy region between that of UTQWs of the pure binary compound with thickness difference of 1 ML, making possible to cover continuously the visible spectral region with CdTe and CdSe UTQWs.
AB - Ultra-thin quantum wells (UTQWs) of CdTe and CdSe should present a emission energy as a function of thickness, however, we have observed that depending on substrate temperature the peak energy is modified: the higher the growth temperature the larger the blue shift. Considering (i) a chemical interaction that produces the substitution of Cd atoms by Zn atoms at the QW-barrier interface, and, (ii) the large Bohr radius of the excitons in II-VI semiconductors, we argue that a few percent substitution of Cd atoms by Zn atoms is perceived as a change in average composition and not as a thickness fluctuation. Since the Cd substitution is a thermally activated process, a larger blue shift is expected at the higher temperatures. Therefore, the UTQWs can be described as made of Zn1-xCdxSe or Zn 1-xCdxTe alloys with high Cd content, x∼1 at the lower substrate temperatures (Ts). Then, the proper selection of T s can be advantageously employed for fine tuning of the excitonic emission in the energy region between that of UTQWs of the pure binary compound with thickness difference of 1 ML, making possible to cover continuously the visible spectral region with CdTe and CdSe UTQWs.
KW - Atomic layer epitaxy
KW - CdSe
KW - CdTe
KW - Excitons
KW - II-VI semiconductors
KW - Photoluminescence
KW - Quantum wells
KW - Ultra-thin quantum wells
UR - http://www.scopus.com/inward/record.url?scp=25144457474&partnerID=8YFLogxK
U2 - 10.1016/j.mejo.2005.04.022
DO - 10.1016/j.mejo.2005.04.022
M3 - Article
AN - SCOPUS:25144457474
SN - 0026-2692
VL - 36
SP - 985
EP - 988
JO - Microelectronics Journal
JF - Microelectronics Journal
IS - 11
ER -