Observation of a deep level in p-type Hg0.78Cd0.22Te with high dislocation density

Abstract

To investigate the possibility that deep levels are associated with dislocations in narrow band gap HgCdTe, deep level transient spectroscopy has been used to study n+-p diodes fabricated on p-type bulk Hg0.78Cd0.22Te samples with either a ‘‘normal’’ dislocation density of about 105 cm−2 or a high dislocation density of about 106 cm−2. These samples which are gold doped with a hole concentration of 1.2×1015 cm−3, have a band gap of about 0.12 eV at 77 K. In samples with a ‘‘normal’’ dislocation density, a deep level of about 80 meV above the valence band was found. However, a midgap level of about 60 meV above the valence band with larger peak amplitude and broader line shapes was found in the sample with a high dislocation density.

Electrical property of n-Hg0.8Cd0.2Te plastically deformed

“…To determine more precisely the position E °, we need to know exactly the density of electrically active dislocations. However, our results agree with a mid-gap level found in p-Hg0.78Cd0.22Te having a high dislocation density [4] and also with the increase in donor concentration associated with the formation of dislocations observed in [2]. Lastly, note also that a possible model for the interaction mechanism between point defects and the moving dislocations has been proposed recently in InP [11].…”

“…Recent investigations [1][2][3] have demonstrated that dislocations originating from material growth or array processing have a dramatic effect on the overall performance of devices. Note also that a deep level located at about 60 meV above the valence band has been evidenced by deep level transient spectroscopy measurements in p-Hg0.78Cd0.22Te having a high dislocation density [4]. In this letter we report on some of our investigations of the electrical properties of n-type Hg0.sCd0.2Te plastically deformed.…”

The Charge Carrier Transport Mechanisms in the Diffusion n–p Junctions Based on MBE CdxHg1—xTe

“…Such estimation should be valid not only for the abrupt junction. Note, that in paper [11] investigating a similar material with x 0X215 by the DLTS method the trap levels with the same energies were found: hole trap with E t1 E v 0.035 eV and electron trap with E t2 E v 0.043 eV at T $ 25 to 30 K. The authors [12] observed the level of E t3 E v 0.062 eV in samples with a large amount of dislocations.…”

Influence of Dislocations on MBE Cd0.22Hg0.78Te/GaAs Photodiodes

“…3). In papers [9][10][11] Figure 2 shows I-V and dI/dV-V characteristics of the investigated diode after applying the pressure. A pressure of less than 2 Â 10 7 N/m 2 practically does not affect the diode characteristics.…”