On determination of Cd1–xZnxTe composition from an analysis of the 4.2, 77 and 295 K edge photoluminescence spectra

Abstract

The known and obtained in this work dependences of the 4.2, 77 and 295 K peak positions hm of the Cd1–xZnxTe edge emission bands induced by: (a) annihilation of free X and bound on shallow neutral acceptors A0 or shallow neutral donors D0 excitons A0X and D0X and (b) recombination of free and shallow donor bound electrons with free holes on Cd1–xZnxTe composition x (x  0.28) are analyzed in detail. It is shown that the 4.2 K peak position of the A0X induced emission band used for the exact x determination could be related with some problems arising from variety of the 4.2 K hm(A0X) vs. x dependences. As a result of the pointed problem, analysis of the 4.2 K hm(A0X) vs. x dependences permits to find the x value with some inaccuracy (some unknown factors shift the energy position of the A0X bound exciton are responsible for this fact). The noticeable (differing from the expected theoretical ones) differences of the peak positions of emission bands hm induced by radiative annihilation of D0X bound excitons at 295 K, radiative recombination of donor bound electrons D0 with free holes h at 300 K and radiative annihilation of free electrons e and holes at 300 K, i.e. of 295 K hm(D0X), 300 K hm (D0h) and 300 K hm (eh) values, accordingly, vs. x dependences are observed and briefly analyzed.

Keywords

• Cd1–xZnxTe composition
• photoluminescence
• free and bound excitons
• accuracy of composition determination