Temperature dependence of the fundamental absorption edge of mercury cadmium telluride

Abstract

We have investigated the temperature dependence of the fundamental absorption edge of a series ofHg 1 _ x Cd x Te alloys (with composition x ranging from 0.5 to 1). Analyzing our data in the light of the three-dimensional theory of direct-allowed excitons, we find precise .values for the fundamental r -r 6 interband transition energy in a temperature range extendmg from o to 300 K. All experi~ental results, including previous data for HgTe and mercury-rich Hg! _ x Cd x Te alloys, are well accounted for using a simple empirical formula:This expression, which is valid for all compositions O<x< 1 and temperatures 0< T<5oo Ie, predicts an alloy composition such that the band~gap energy is temperature independent: We find x = 0.505. Finally, it can be used for technological application purpose (far-infrared detection as well as optical-fiber communications performed at realistic values of the temperature) and gives accurate values for the temperature and composition dependence of the effective mass in the semiconducting range of alloys.

Free‐exciton absorption in bulk CdTe: temperature dependence

“…It seems that the actual generally accepted value of E g is 1.512 ± 0.003 eV, as deduced from photoreflectance and electroreflectance methods [1,3]. Studies on the temperature dependence of E g [4][5][6][7][8][9][10] of CdTe are only slowly converging. However, the knowledge of E g (T) is needed for modeling of transport properties and investigation of defect states in the gap at higher temperatures.…”

Band structure of semimagneticHg1−yMnyTequantum wells

“…16 The band structure parameters for HgTe and CdTe at T = 0 K are listed in Table I. The dependence of the band gap (E g ) of Hg 1−x Cd x Te on the temperature and composition x is determined from the empirical expression according to Laurenti et al 17 The valence band offset between HgTe and CdTe is taken to be equal to 570 meV at T = 0 K, in agreement with recent experiments, 18 and is assumed to vary linearly with x. …”

Prediction of a Weyl semimetal inHg1−x−yCdxMny

“…All lattice parameters are linearly interpolated in x except for the zero-field gap at y = 0. We use a quadratic interpolation of the last parameter from the literature 21 .…”