Carrier density and compensation in semiconductors with multiple dopants and multiple transition energy levels: Case of Cu impurities in CdTe

Abstract

Doping is one of the most important issues in semiconductor physics. In many cases, when people describe carrier concentration as a function of dopant density and Fermi energy, they usually assume only one type of dopant with single transition energy level in the system. However, in reality, the situation is often more complicated, that is, in a semiconductor device, it usually contains multidopants and each can have multitransition energy levels. In this paper, using detailed balance theory and first-principles calculated defect formation energies and transition energy levels, we derive formulas to calculate carrier density for semiconductor with multidopants and multitransition energy levels. As an example, we studied CdTe doped with Cu, in which V Cd , Cu Cd , and Cu i are the dominant defects/impurities. We show that in this system, when Cu concentration increases, the doping properties of the system can change from a poor p-type, to a poorer p-type, to a better p-type, and then to poor p-type again, in good agreement with experimental observations.

Native point defects in CuIn1−xGaxSe2: hybrid density functional calculations predict the origin of p- and n-type conductivity

“…This factor depends on the electronic degeneracy, including spin degeneracy 40 . The electronic degeneracies can be obtained as follows, by investigating the levels due to the defect.…”

Silver-Doped Cu2SnS3Absorber Layers for Solar Cells Application

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Correlation between the electronic structures and diffusion paths of interstitial defects in semiconductors: The case of CdTe

“…Without these treatments, CdTe is almost intrinsic (the hole concentration is very low, < 10 14 cm −3 ) with short minority carrier lifetime (< 1 ns), and the efficiency is low (< 10%) 9,10 . Theoretically, it has been found that both Cl and Cu can help to passivate the dangling-bond states at grain boundaries in CdTe, and the incorporation of proper amounts of Cu and Cl can also enhance the p-type doping by forming Cu on Cd site (Cu Cd ) and the A-center (V Cd + Cl Te ) acceptors 11,12 . It has been well known that the diffusion behavior of interstitial elements in semiconductors is greatly influenced by its electronic structures 13,14 .…”