Probing localized states distributions in semiconductors by Laplace transform transient photocurrent spectroscopy

Abstract

Effect of missing short-time data on recovery of the electronic density of states from TPC data 1.5 Application of the approximate and exact methods to experimental data obtained on amorphous and crystalline materials. 1.5.1 Exact methods-E L T and T i k h o n o v regularization methods 55 Light-induced meta-stable states in PECVD a-Si: H 55 'Discrete' levels in single crystal Tin-doped C d T e. 1.5.2 Approximate methods (L T and H L T methods) Light-induced meta-stable states in PECVD aS i : H Discrete levels in single crystal Tin-doped C d T e I I. II. Time of Flight Experiment 2.1 Early work on TOF experiment 2.2 Multiple Trapping model in terms of TOF experiment Brief mathematical outline 2.3 T i k h o n o v Regularization and E L T methods in the context of TOF experiment 71 T i k h o n o v Regularization method 71 E L T in a post-transit (post-recombination) regime 2.4 Application to simulated and experimental data Simulated data Two discrete levels Exponential distribution with a G a u s s i a n feature superimposed 75 Experimental data Appendices 80 References 83

Determination of defect level parameters in semi-insulating GaAs:Cr from transient photocurrent experiment

“…However, to avoid the overestimation of rDOS due to k B T broadening in the approximate expression derived by Brüggemann et al [3], one has to use low temperature TPC. The alternative to overcome this limitation is to use an exact matrix resolution based on Tikhonov regularization [8,12], which we have applied to our experimental data. The basis of the method we used was developed by Hansen [13], but this method has been modified to give an iterative procedure.…”

“…A comparison of the results obtained on the same semi-insulating GaAs crystals was even the subject of a previous paper [6]. The TPC experiment was mainly applied to amorphous semiconductors [5,7] and, more recently, to CdTe crystals [8].…”