The energy distribution of localized states in amorphous arsenic triselenide from transient photoconductivity measurements

Abstract

AbstracLDC conductivity, time of flight (mF) and Vansient photoconductivity (TP)measurements were performed in order to characterize samples of amorphous arsenic triselenide prepared by thermal evaporation. Analysis of the hole d e r drift mobility data provides strong evidence for carrier interaction with a s"cbxed distribution of defect centres rather than the broad featureless distribution that has in the past been proposed for arsenic uiselenide. Deviations from power law behaviour in the TP data also provide evidence for the existence of smctm. We applied the 'intuitive' thermalimion spectroscopic technique to the data and discovered defect centres situated at an energy position E1 -0.42 eV within the mobility gap.At high temperature the thermalization depth of holes is limited by a set of recombination centres sitnated,at El -0.65 eV above the valence band edge.

Abnormal low-temperature behavior of a continuous photocurrent in Bi2S3 nanowires

“…[1][2][3][4][5] For large time-domain photodetectors, the photocurrent relaxation in the semiconductors is greatly inuenced by the capture of nonequilibrium carriers on defect or impurity deep states. 6,7 Generally, these trap states can rapidly capture one kind of carrier (for example, holes), prolong the lifetimes of photogenerated electrons and improve the photocurrent gains. 8 Pioneering work has been done to study the effects of trap states, such as Shockley-Read-Hall recombination and trapping processes.…”

Effect of Electrical Contact on the Performance of Bi2S3 Single Nanowire Photodetectors

“…All curves are measured under the same conditions with a bias of 0.1 V. The response time is calculated to be about 50 ms from Figure 3 c and d. It is known that the response time for photodetectors is mainly controlled by the trap states in the samples. [45,46] For non-ohmic contact devices, there was a large barrier at the AuÀBi 2 S 3 interfaces. If the focused laser illuminated the AuÀBi 2 S 3 interface, due to the SPV effect, many electrons in Bi 2 S 3 were excited from the valence band to conduction band and then separated with the help of built-in potential.…”