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We discuss the device applications of a new impact ionization model. This model is based on a new formulation of the impact ionization rate for bulk semiconductors, derived from solvable high‐field Boltzmann transport equations. The model inputs are relaxation times which simulate the dominant electron‐phonon scatterings and are calibrated by realistic Monte Carlo simulations. Our impact ionization model is shown to be physically motivated and is easily implemented in the standard hydrodynamic device simulators HFIELDS and FIELDAY. An efficient numerical scheme is used to simulate three thin‐base silicon bipolar transistors. Results based on this impact ionization model are found to agree well with the experimental multiplication factors over a large range of applied voltages. These results are contrasted with the more phenomenological treatment of Scholl and Quade which is shown to be a low‐field limit of our model.

We propose a modified discretization for the current continuity equation in the hydromodel for semiconductors. It combines ease of implementation within existing codes and robustness, even for extremely short devices. Some computational results for one and two dimensional structures are given.

The purpose of this paper is to assess the motivations of timber firms in Ghana to undertake environmental accounting and reporting (EAR) and the perceived benefits from it.

Survey method involving primary data from a census of 13 timber firms in Kumasi (Ghana) and descriptive statistics including Kendall’s coefficient were used to analyze the perceptions of practitioners on EAR.

The study offered support for the political economy, legitimacy and stakeholder theories generally applied to the study of EAR. Specifically, the study concluded that EAR is common to timber firms in Ghana. Pressure from government, media, shareholders’ influence and the existence of environmental committee or department in the company are perceived to influence timber firms’ level of environmental disclosure. Meanwhile, perceived benefits from EAR include fostering cordial relationship between timber firms and the society, preventing government fines and improving firm reputation.

The presence of biases in the responses of survey method studies can be difficult to eliminate. However, given the benefits associated with getting practitioners views on EAR and the reliability/validity procedures that the instruments and respondents were subjected to, this weakness was reduced to its barest minimum.

The study recommends that governments should adopt green tax policy to encourage EAR while regulatory bodies make EAR mandatory.

This study contributes to the discussion on EAR from the perspective of practitioners in the timber industry of Ghana, which has been neglected in previous studies.

The purpose of this paper is to investigate the level of voluntary compliance with, and disclosure of, corporate governance (CG) best practices, and the extent to which board characteristics and shareholding structures can explain discernible differences in the level of voluntary CG disclosure in a number of emerging Middle Eastern and North African (MENA) economies.

The paper uses a number of multivariate regression methods, namely, ordinary least squares, weighted, non-linear, lagged-effects, two-stage least squares and fixed-effects regression techniques to analyse data collected for a sample of listed corporations in emerging MENA economies from 2009 to 2014.

First, in general, MENA listed firms have a relatively lower level of voluntary compliance with, and disclosure of, CG practices compared to listed firms in developed countries. Second, the evidence suggests that corporate board characteristics, including board diversity, have a positive association with the level of voluntary CG disclosure. In contrast, the findings indicate that unitary board leadership structure, director shareholdings and government shareholdings negatively impact on the level of voluntary CG disclosure. The study does not, however, find any evidence to suggest that family shareholdings have any significant relationship with the level of voluntary CG disclosure. The findings are generally robust to alternative measures and potential endogeneity problems.

This is one of the first empirical efforts at investigating the association between CG mechanisms and voluntary disclosure in emerging MENA economies that observably relies on a multi-theoretical framework within a longitudinal cross-country research setting.