Identification of Buffer and Surface Traps in Fe-Doped AlGaN/GaN HEMTs Using Y21 Frequency Dispersion Properties

The buffer and surface trapping effects on low-frequency (LF) Y-parameters of Fe-doped AlGaN/GaN high-electron mobility transistors (HEMTs) are analyzed through experimental and simulation studies. The drain current transient (DCT) characterization is also carried out to complement the trapping investigation. The Y22 and DCT measurements reveal the presence of an electron trap at 0.45–0.5 eV in the HEMT structure. On the other hand, two electron trap states at 0.2 eV and 0.45 eV are identified from the LF Y21 dispersion properties of the same device. The Y-parameter simulations are performed in Sentaurus TCAD in order to detect the spatial location of the traps. As an effective approach, physics-based TCAD models are calibrated by matching the simulated I-V with the measured DC data. The effect of surface donor energy level and trap density on the two-dimensional electron gas (2DEG) density is examined. The validated Y21 simulation results indicate the existence of both acceptor-like traps at EC –0.45 eV in the GaN buffer and surface donor states at EC –0.2 eV in the GaN/nitride interface. Thus, it is shown that LF Y21 characteristics could help in differentiating the defects present in the buffer and surface region, while the DCT and Y22 are mostly sensitive to the buffer traps.

Cultivating Ownership of Development Aid: The Role of Civil Society in the Pacific

<p>The principle of ownership and the idea that development aid should be owned by recipients has emerged within the last two decades in key statements from a series of international meetings between major donors and partners, most prominently since the 2005 Paris Declaration when ‘ownership of development aid’ became the first Principle of Aid Effectiveness. The principle was applauded particularly by the governments of rich donor states, but also by their specialist aid agencies and representatives of civil society. However, despite the endorsement and praise of the principle of ownership by all donors and stakeholders, confusion and lack of clarity remains as to what exactly ownership of development aid means especially in terms of policy and practice in the work of development actors. The core proposal of this thesis is that the principle of recipient ownership of development aid, apparently so important at the highest international levels of discussion, must be defined, broken down into relevant ingredients, taken into consideration in terms of policy and practice, and measured. Otherwise, the principle is nothing but empty rhetoric. It is logical to suggest that to have any policy value political concepts should be definable and measureable. Hence, the thesis argues that if one can formulate the relevant ingredients of ownership, one can carefully investigate factors that increase or decrease those ingredients. This is the focus of this thesis. Field research in the Pacific Islands used a mixed methodology that included gathering data on completed development projects and interviewing government officials, major donor officials, other deliverers of aid – particularly the civil society organisations (CSOs) – and especially the project beneficiaries at the grassroots. Projects where CSOs demonstrated particularly close engagement with the communities and beneficiaries were chosen as case studies. Analysing and deconstructing these mechanics and ingredients of ownership produced a new definition for ‘ownership of development aid’ and a range of variables for an Ownership Index and for Ownership Guidelines. These combined tools presented in this research should assist professionals to promote, cultivate and measure ownership of development outcomes that project beneficiaries will maintain, protect and improve over time.</p>

Is Hegemony in the South Pacific possible?

<p>Hegemony is a concept associated with ‘superordinate’ powers equated to a sovereign state that has amassed great wealth and prowess. It is instrumental in developing institutions and defines the ‘rules of the game’. This paper explores the theory, that to be a hegemon in the region, a super-powerful state requires more than controlling inherent material capabilities. The rule of force and ideological thinking are now inadequate to keep a super state as the dominant or hegemonic power. There are distinct shifts of power dynamics from a realist perspective which includes John Mearsheimer’s “hard” and “latent power” to Evelyn Goh’s ideational thinking and the “cultural and social” components. China-US feature strongly in this paper. It will explore if hegemony is possible in the South Pacific Region (SPR). The region covers a large blue ocean space that has a number of small Pacific Island sovereign states and New Zealand and Australia. Geographically, the region has three distinct sub-regions namely, Melanesia, Polynesia, Micronesia. It is within these sub-region that ‘ordering’ of states occur with New Zealand, Australia and Papua New Guinea occupying larger landmasses and having bigger populations than the smaller island states. The emergence of China with its foreign policy interests, ‘soft power’ and blue ocean naval strategy into the SPR has attracted attention from the traditional powers inside and outside the region. In response, US, a superpower identified as the hegemon in the Pacific region, post colonization era during the 20th and the early 21st century, earning its name as ‘Pacific Theatre or The American Lake’, is re-adjusting its strategy to counter China’s interest. An analysis based on the ranking table with specific parameters will assist in determining which of the powers, in this instance, US and China will occupy the top of the rank. Even so it may not be adequate to claim hegemonic status in the region. This paper agrees that ‘hegemony’ is specific to the region of its interest. Power is measured in terms of its relative gains. The primary criteria in the ranking table will measure Aid given by donor countries to Pacific Islands. Although New Zealand and Australia are within the region they are ranked as donor states rather than recipients like island states in the sub-region.</p>

Is Hegemony in the South Pacific possible?

<p>Hegemony is a concept associated with ‘superordinate’ powers equated to a sovereign state that has amassed great wealth and prowess. It is instrumental in developing institutions and defines the ‘rules of the game’. This paper explores the theory, that to be a hegemon in the region, a super-powerful state requires more than controlling inherent material capabilities. The rule of force and ideological thinking are now inadequate to keep a super state as the dominant or hegemonic power. There are distinct shifts of power dynamics from a realist perspective which includes John Mearsheimer’s “hard” and “latent power” to Evelyn Goh’s ideational thinking and the “cultural and social” components. China-US feature strongly in this paper. It will explore if hegemony is possible in the South Pacific Region (SPR). The region covers a large blue ocean space that has a number of small Pacific Island sovereign states and New Zealand and Australia. Geographically, the region has three distinct sub-regions namely, Melanesia, Polynesia, Micronesia. It is within these sub-region that ‘ordering’ of states occur with New Zealand, Australia and Papua New Guinea occupying larger landmasses and having bigger populations than the smaller island states. The emergence of China with its foreign policy interests, ‘soft power’ and blue ocean naval strategy into the SPR has attracted attention from the traditional powers inside and outside the region. In response, US, a superpower identified as the hegemon in the Pacific region, post colonization era during the 20th and the early 21st century, earning its name as ‘Pacific Theatre or The American Lake’, is re-adjusting its strategy to counter China’s interest. An analysis based on the ranking table with specific parameters will assist in determining which of the powers, in this instance, US and China will occupy the top of the rank. Even so it may not be adequate to claim hegemonic status in the region. This paper agrees that ‘hegemony’ is specific to the region of its interest. Power is measured in terms of its relative gains. The primary criteria in the ranking table will measure Aid given by donor countries to Pacific Islands. Although New Zealand and Australia are within the region they are ranked as donor states rather than recipients like island states in the sub-region.</p>

Cultivating Ownership of Development Aid: The Role of Civil Society in the Pacific

<p>The principle of ownership and the idea that development aid should be owned by recipients has emerged within the last two decades in key statements from a series of international meetings between major donors and partners, most prominently since the 2005 Paris Declaration when ‘ownership of development aid’ became the first Principle of Aid Effectiveness. The principle was applauded particularly by the governments of rich donor states, but also by their specialist aid agencies and representatives of civil society. However, despite the endorsement and praise of the principle of ownership by all donors and stakeholders, confusion and lack of clarity remains as to what exactly ownership of development aid means especially in terms of policy and practice in the work of development actors. The core proposal of this thesis is that the principle of recipient ownership of development aid, apparently so important at the highest international levels of discussion, must be defined, broken down into relevant ingredients, taken into consideration in terms of policy and practice, and measured. Otherwise, the principle is nothing but empty rhetoric. It is logical to suggest that to have any policy value political concepts should be definable and measureable. Hence, the thesis argues that if one can formulate the relevant ingredients of ownership, one can carefully investigate factors that increase or decrease those ingredients. This is the focus of this thesis. Field research in the Pacific Islands used a mixed methodology that included gathering data on completed development projects and interviewing government officials, major donor officials, other deliverers of aid – particularly the civil society organisations (CSOs) – and especially the project beneficiaries at the grassroots. Projects where CSOs demonstrated particularly close engagement with the communities and beneficiaries were chosen as case studies. Analysing and deconstructing these mechanics and ingredients of ownership produced a new definition for ‘ownership of development aid’ and a range of variables for an Ownership Index and for Ownership Guidelines. These combined tools presented in this research should assist professionals to promote, cultivate and measure ownership of development outcomes that project beneficiaries will maintain, protect and improve over time.</p>

Impact of Surface States and Aluminum Mole Fraction on Surface Potential and 2DEG in AlGaN/GaN HEMTs

The presence of surface traps is an important phenomenon in AlGaN/GaN HEMT. The electrical and physical properties of these surface traps have been analyzed through the study of 2DEG electron concentration along with the variation of aluminum percentage in the barrier layer of HEMT. This analysis shows that from deep to shallow donors, the percentage change in electron density in 2DEG gets saturated (near 8%) with change in aluminum concentration. The depth of the quantum potential well below the Fermi level is also analyzed and is found to get saturated (near 2%) with aluminum percentage when surface donor states energy changes to deep from shallow. The physics behind this collective effect is also analyzed through band diagram too. The effect of surface donor traps on the surface potential also has been discussed in detail. These surface states are modeled as donor states. Deep donor (EC − ED = 1.4 eV) to shallow donor (EC − ED = 0.2 eV) surface traps are thoroughly studied for the donor concentration of 1011 to 1016 cm−2. This study involves an aluminum concentration variation from 5 to 50%. This paper for the first time presents the comprehensive TCAD study of surface donor and analysis of electron concentration in the channel and 2DEG formation at AlGaN–GaN interface.

Do Hybrid Legal Systems Matter in Foreign Legal-Aid Programmes? Some Philosophical Aspects of Legal Aid in Uzbekistan as Provided by the Donor States

Since the fall of socialism in Eastern Europe, the former Soviet Union, and some states of Southeast Asia, the international financial institutions and individual donor states have initiated wide-scale legal-aid programmes to assist these states in their transition from socialism to a market economy. Whereas the aid from financial institutions vis-à-vis recipient states is often agreed upon specific conditionalities, the donor states design their foreign legal aid according to individual preferences, although sometimes with references to universal goals. Currently, various donor states provide legal aid to Uzbekistan. Given the fact that Uzbekistan is the former Soviet Republic that still bears multiple traces of a socialist legal system and additionally integrates indigenous informal law, this research provides an analysis of how different donor states base their legal-aid activities on entirely different philosophies and levels of gravity, and how receptive the hybrid structure of Uzbekistan’s law is towards such aid.

Blessing or Curse?

Earmarked funding to international organizations (IO s) has increased significantly over the past two decades. International relations scholars have examined the causes of this trend, but know less about its effects on UN entities. This article identifies different types of earmarked funding, varying from low to high discretion delegated to IO s. Secondly, it examines trends in the UN Development Programme and UN Children’s Fund and finds that both have significant proportions of earmarked funding with low discretion. Drawing on thirty interviews, the article notes four implications of tightly earmarked financing: 1) higher transaction costs for IO s; 2) less predictable funding; 3) overhead costs that are rarely covered; and 4) increasing competition for financing. Overall, the article highlights that earmarked financing exists on a spectrum from tight to minimal control by donor states, and this has important implications for multilateralism.

Defect controls by silicon doping in non-polar a-plane AlGaN epi-layers

Deposition of high-quality Si-doped crystalline AlGaN layers, especially non-polar-grown AlGaN layers, is critical and remains difficult in preparing AlGaN-based light-emitting diodes (LEDs), as the Si-doping-induced variations of crystalline structures are still under exploration. In this work, structural characterizations of Si-doped AlxGa1−xN layers were carried out by associating with examination of their carrier recombination behaviors in photoluminescence (PL) processes, to clarify the physical mechanism on how Si doping controls the formation of structural defects in AlGaN alloy. The obtained results showed that Si doping induced extrinsic shallow donor states and increased the densities of point defects like cation vacancies. On the contrary, Si doping suppressed formation of line defects like dislocations and planar defects like stacking faults with suitable doping concentration. These results may guide further improvement of UV-LEDs based on AlGaN alloy.