Electrical properties of HgCdTe films grown by MOCVD and doped with as

Abstract

Electrical properties of HgCdTe films grown by metal-organic chemical vapour deposition (MOCVD) on GaAs substrates and doped with the As acceptor during the growth were studied. Discrete mobility spectrum analysis was used to extract the parameters of the as-grown films and films after ion milling and during prolonged relaxation of milling-induced defects. The measurements revealed significant compensation of the as-grown MOCVD HgCdTe with As on Te sites being the main defect, residual donor concentration of the order of (2–5)×1015 cm−3, and the presence of some unidentified defects.

Electrical profiling of arsenic-implanted HgCdTe films performed with discrete mobility spectrum analysis

“…The R H (B) and σ(B) dependences were analysed using the discrete MSA (DMSA) procedure [18,19]. In this method, a primary mobility spectrum envelope (MSE) was calculated first from the measured R H (B) and σ(B) dependences using the classical MSA algorithm developed by Beck and Anderson [20].…”

Optical and Structural Properties of Hg-=SUB=-0.7-=/SUB=-Cd-=SUB=-0.3-=/SUB=-Te Epitaxial Films

“…2 shows normalized spectra of the PL samples A, B, C and D (Fig. 2, a), and E (of the paper [14]), H and J (Fig. 2, b), as recorded at 85 K. The full width at the half-height (the half-width) of the spectra recorded at this temperature was 14.8 meV for the sample A, 15.0 meV for the samples B and C, 12.6 meV for the sample D, 17.2 meV for the sample I, 15.7 meV for the samples J and K and 19.4 meV for the sample H. The spectra of the MOVPEgrown samples E and F were substantially wider, and their half-widths at 85 K were 31 and 28 meV, respectively.…”

“…For the E and F samples, the photoconductivity spectra were recorded at T = 85 K (for the E sample the spectrum is given in the paper [14]). The position of the half-drop of the long-wave photoconductivity interface for both the samples corresponded to the energy of ∼ 0.28 eV, which corresponded to a claimed composition of the film as per the used dependence E g (x, T ).…”

“…After the growth, the samples were annealed in the Hg saturated vapor at 230 • C during 48 h. For comparison, the samples of the bulk crystals were also studied, and the crystals were grown in JSC " Chistye Metally" (Ukraine) by a modified method of vertically directed crystallization (VDC) with make-up out of the solid phase. The studies also involved the MOVPE-produced layers and some properties thereof have been previously reported in the paper [14]. They have been grown on the GaAs(110) semi-insulating substrates with the Cd(Zn)Te buffer layer in the VIGO System S.A. company (Poland) as per a technology similar to that described in the paper [3].…”

Background donor concentration in HgCdTe

“…It can be noted that with MOCVD technology, vacancy concentration can be reduced far below the equilib− rium level simply by adjusting growth conditions, so the BDC in such material is very important [27]. We studied films grown with MOCVD on CdZnTe and CdTe−buffered semi−insulating (111)B GaAs substrates at VIGO System [28] and with MBE on (311) GaAs [29]. The relaxation of n 77 and μ n77 of two MBE and two MOCVD films with x »0.2 grown on GaAs substrate is shown in figure 8 along with the similar data for an isother− mal vapour phase epitaxy (ISOVPE, yet another vapour− −phase epitaxy method) arsenic−doped film grown on a CdTe substrate at Ivan Franko National University in Lviv, Ukraine [17].…”