Low Molecular Weight Organic Semiconductors

Low Molecular Weight Organic Semiconductors......Page 5
Contents......Page 7
Preface......Page 9
1: Introduction......Page 11
1.1: Electronic Surface Properties of Inorganic Semiconductors......Page 14
1.1.1: Surface Band Bending......Page 15
1.1.2: Surface Dipoles......Page 18
1.1.3: Passivation of GaAs Surfaces......Page 19
1.2.1: Metal–Semiconductor Contacts......Page 28
1.2.2: Metal Contacts on GaAs......Page 31
2: Growth of Thin Films......Page 35
2.1: Purification......Page 36
2.2: Organic Molecular Beam Deposition......Page 38
2.3: Organic Vapor Phase Deposition......Page 39
3: Structural Analysis......Page 41
3.1: Scanning Probe Microscopy......Page 44
3.1.1: STM on PTCDA/Au(111)......Page 46
3.1.3: AFM on PTCDA and DiMe-PTCDI/S-passivated GaAs(100)......Page 48
3.2: X-Ray Diffraction (XRD)......Page 50
3.2.1: XRD on PTCDA grown on GaAs and Si......Page 51
3.3: Low-Energy Electron Diffraction......Page 55
3.3.1: LEED on PTCDA/Au(111)......Page 56
3.3.2: micro-LEED on Pentacene/Si(111)......Page 57
4: Optical Spectroscopy......Page 59
4.1: Photoluminescence......Page 65
4.1.1: PL on PTCDA/Si(111)......Page 66
4.2: Raman Spectroscopy......Page 70
4.2.1: Raman Spectroscopy on PTCDA Crystals and Thin Films......Page 72
4.3: Infrared Spectroscopy......Page 80
4.3.1: Assignment of Vibrational Modes......Page 81
4.3.2: IR on PTCDA/Si......Page 83
4.3.3: IR on DiMe-PTCDI......Page 84
4.4.1: Optical Constants of PTCDA and DiMe-PTCDI......Page 88
4.4.2: Optical Constants of Crystalline and Thin-Film Pentacene......Page 91
4.5: Reflection Anisotropy Spectroscopy......Page 93
5: Electronic and Chemical Surface Properties......Page 95
5.1: Photoemission Spectroscopy......Page 100
5.1.1: UPS on PTCDA and DiMe-PTCDA......Page 103
5.1.2: Energy Level Alignment at PTCDA and DiMe–PTDI Interfaces......Page 105
5.1.3: PTCDA/DiMe–PTCDI Metal Interfaces......Page 113
5.1.4: Bandstructure of PTCDA and DiMe-PTCDA......Page 119
5.2: Inverse Photoemission......Page 123
5.2.1: Band Gaps of Perylene Derivatives......Page 125
5.3: Total Current Spectroscopy......Page 126
5.4: Near Edge X-ray Absorption Fine Structure Spectroscopy......Page 128
6: Charge Transport......Page 133
6.1: Time-of-flight measurements (TOF)......Page 135
6.2: Thin Field Effect Transistor (TFT) Mobilities......Page 138
6.3: I/V Curves of Ag/GaAs (100) Schottky Contacts......Page 140
6.4: Charge Carrier Mobilities......Page 146
6.5: Simulation of IV Curves......Page 147
6.6: Chemical Stability......Page 149
6.7: Deep level transient spectroscopy......Page 152
6.7.1: In-situ diagnostics of Ag/Alq3/PTCDA/GaAs devices......Page 155
6.7.2: Ex situ diagnostics of Ag/Alq3/PTCDA/n-GaAs devices......Page 157
6.8: Organic-Modifi ed Schottky Diodes for Frequency Mixer Applications......Page 159
References......Page 163
Index......Page 173