Forward bias capacitance spectroscopy for characterization of semiconductor junctions: Application to a-Si:H p-i-n diode

Dynamics of electronic transitions and frequency dependence of negative capacitance in semiconductor diodes under high forward bias

“…We observed that as the forward bias increases, the reactive component of the impedance demonstrates negative capacitance. Higher magnitude of this negative capacitance (NC) for lower applied modulation frequencies has also been observed by many groups in electroluminescent devices 5,6,7 and also in other semiconductor devices 8,9 .…”

“…Since the activation of this high frequency defect response (peak 2) with increasing bias is not dependent on slower modulation frequencies, V NC in region I of Figure 2(b) also does not vary much with changing modulation frequencies. Note that in some of the Si-based devices, it has been reported 9,18 that the frequency dependence of NC is qualitatively similar to that of ELDs. We argue that this could be due to the interplay of different time scale processes in a manner similar to ELDs.…”

“…Higher magnitude of this NC for lower applied modulation frequencies has also been observed by many groups in electroluminescent devices [5][6][7] and also in other semiconductor devices. 8,9 Here, we report qualitatively opposite dynamic behavior of NC in two sets of diodes with different functionalities: (a) III-V based electroluminescent diodes (ELDs): (i) InGaAs based quantum dot laser (QDL) diodes grown by Molecular Beam Epitaxy (MBE) on (100) GaAs substrates. A 0.7 lmthick GaAs buffer layer was grown before deposition of the In 0.5 Ga 0.5 As strained layer at 450 C. The structure was completed with a 25 nm GaAs cap.…”

Revealing the Negative Capacitance Effect in Silicon Quantum Dot Light-Emitting Diodes via Temperature-Dependent Capacitance-Voltage Characterization

“…The trap states need to fulfill the condition ω AC = τ −1 trap with the angular frequency of the AC signal ω AC = 2πf AC , while f AC is the measurement frequency. [34], [37] From this condition, an energy level known as demarcation [34], [36], [38]- [41] can be determined by rearranging Equation. 1:…”

“…This energy is also called cut-off [41], [42] or thermal activation energy [43], [44] but for the rest of this work, E ω will be referred to as demarcation energy. A schematic representation of the demarcation energy is given in Figure 2.…”