Acceptor states in HgCdTe films grown by molecular‐beam epitaxy on GaAs and Si substrates

Abstract

A study of defects in HgCdTe films grown by molecular‐beam epitaxy on GaAs and Si substrates was performed. Variable‐temperature photoluminescence (PL) and carrier lifetime measurements were carried out on as‐grown films and films subjected to post‐growth annealings. Films grown on GaAs substrates appeared to be mostly free from defects providing energy states within the bandgap, yet specific acceptor states were generated in these films under conditions associated with mercury deficiency. The properties of films grown on Si substrates were mostly governed by two types of uncontrolled defects. Relatively deep levels with energy 40 to 70 meV were revealed with the use of PL measurements, yet their effect on the lifetime was not traced. The lifetime value was rather determined by other type of defects with energy depth of ∼30 meV. Possible relation of these defects to the specifics of MBE growth of HgCdTe on Si substrates is discussed. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Температурная зависимость уровня Ферми в узкозонных объемных пленках HgCdTe при различной концентрации вакансий ртути

“…Вакансии ртути упоминаются во многих работах (см., например, [16][17][18][19][20]), однако консенсуса в отношении спектра дырочных состояний для таких акцепторов, в том числе и энергий ионизации A 0 2 -центра и A −1 2 -центра, в настоящее время нет, как и детальной теории, аккуратно описывающей спектр состояний " двухзарядовых" центров. Анализ спектров поглощения в полупроводниках с двухзарядовыми центрами представляет значительную сложность в силу необходимости нахождения парциальных концентраций носителей заряда на разных состояниях таких центров, что является сложной задачей, требующей дополнительных экспериментальных данных и их анализа, как, например, для двойных доноров в кремнии [21], где энергия связи центров много меньше ширины запрещенной зоны и задача является униполярной.…”

Temperature dependence of the Fermi level in HgCdTe narrow-gap bulk films at different mercury vacancy concentrations

“…Mercury vacancies are mentioned in many papers (see, for example, [16][17][18][19][20]), but currently there is no consensus on the spectrum of hole states for such acceptors, including ionization energies A 0 2 -center and A −1 2 -center, as also is no detailed theory that accurately describes the spectrum of states of " two-charge" centers. The analysis of absorption spectra in semiconductors with two-charge centers is of considerable complexity due to the need to find partial concentrations of charge carriers at different states of such centers, which is a complex problem requiring additional experimental data and their analysis, as, for example, for double donors in silicon [21], where the bond energy of the centers much smaller than the band gap and the problem is unipolar.…”

Photoluminescence in Mercury Cadmium Telluride – a Historical Retrospective. Part II: 2004–2022

“…The next cycle of works at the Ioffe Institute was primarily devoted to the study of acceptors in MBE-grown MCT [91][92][93][94][95]. One of the reasons for this study was the development of the p + -n-type photodiodes, which are characterized by much lower dark currents than their n +p counterparts.…”

“…10. Temperature dependence of the relation of intensity of PL interband recombination line I(c-v) to that of a transition to a deep acceptor levelI(c-A) for two as-grown MCT/Si films with x ~ 0.4 (replotted using the data from Ref [95]…”