Contacts to ZnO (zinc oxide) Research Paper Example | Topics and Well Written Essays - 3500 words

Contacts to ZnO (zinc oxide) - Research Paper Example Furthermore, as ZnO films and crystals may be interfaced with a variety of metals to form schottky and ohmic contacts. ZnO contacts have the capability of replacing conventional or time tested materials that have been used including the AlInGaN system and so, ZnO contacts may pave way for more reliable and less costly appliances. ZnO has a hexagonal or wurtzite crystal structure. The wurtzite structure is formed with the Zn atoms being tetrahedrally coordinated with four O atoms. This allows the Zn d shell electrons to hybridize with the p shell of O. ZnO has a density of 5.606 g/cm3, melting point of 1975Â °C and exciton binding energy of 60mEV. The compound is a direct band gap semi conductor that has Eg=3.2eV. ZnO can be molded to produce desired electrical properties by divalent subsititution on the cation site. ZnO supports both n-type and p-type doping. The presence of Zn interstitials, O vacancies and hydrogen .The intrinsic level defects that cause n-type doping are 0.01-0.05eV below the conduction band. The material possesses an intrinsic direct band gap, a strong exciton state and gap states due to the presence of point defects. A study of the optical properties of ZnO by use of photoluminesence, photoconductivity and absorption confirms the presence of point defects[10].. ZnO is a wide gap semi conductor. Wide gap semi conductors are known to be more susceptible to n type doping; such as n-type doping through of ZnO through addition of excess Zn, Aluminum or Gallium. In this instance ZnO can be easily doped to form n-type material rather than p-type material. The reason behind the difficulty in doping ZnO to form p-type material can be linked to a number of reasons. In some cases, the inate point defects within the material compensate for the additional impurity by forming deep level traps. In other instances strong lattice relaxations push the dopant energy level deeper into the

Comparison of the constraining factors of local employment Essay

Comparison of the constraining factors of local employment law(national law) between USA and UK - Essay Example UK, like the other economies in the world, has also suffered an economic decline because of the economic crisis, much more due to its exposure in the financial sector. (CIA world Factbook). Because of this, the country was pressed into a recession in the middle of 2008. Labor has been affected because unemployment rate stepped up to 7.9% in 2010 as against 7.6 %in 2009. As shown in table below, the year 2011 has the highest unemployment rate in UK since 2003. Fig. 1. Unemployment rate in UK Source: CIA World Factbook, cited in Index Mundi Political environment Workers in UK are protected by the employment law. UK implements a national minimum wage amount of ?6.08 per hour to workers above 21, while ?4.98 is paid to workers with ages 18-20. Wage rate is much lower to 16-17 that is ?3.68S and for apprentice rate is ?2.60.how below are the entitlement of workers under this law. Working hours in UK should not exceed 48 hours, but there are instances that exempt certain class of workers f rom this. Doctors, domestic servants, police and army personnel and those engaged in emergency work are exempted in48 hours rule. All workers are entitled to holiday pay of 5.6 weeks paid annual leave, sick leave, of 5.5 times, rest breaks and overtime pay. These privileges are stipulated in an employment contract that has a term expiry. Sunday is a work day in UK (direct.gov.) Immigration rules. All foreign workers eager to work in UK must obtain a working permit. To qualify, applicant must qualify in the points based system for immigration for work based categories. Investors, entrepreneurs and exceptionally talented person, called as high-value migrants should pass the point system, and they are welcome to UK without the need for job offers. Other qualifications to work in UK are being a skilled worker, temporary worker, domestic worker, or representative of an overseas firm, broadcasting firm or a newspaper organization (UK Border Agency) Demographics Population of UK as of 2011 is 62,678,362. Age structure of working group is divided into 15-64 age bracket with male having 20,979,000 and female 20,500,000. With a labor force of 31.45 million part of this belong to women labor (CIA World Factbook, 2011). The constraint for employment is found to be the gender gap of pay that becomes barriers to women working in occupations traditionally done by men. According to Facts Fawcett society, the gender pay gap is estimated at 15.5% that could be worth L15 to L23 billion. The study of this society showed that 64% of lowest paid workers are women, and many of them are doing part-time work which is paid lower than the hourly rate work. 2. United States Economy The United States has a market oriented economy wherein businesses, organizations and individuals are allowed to make their own decisions while the federal government buys goods and services in the marketplace. US enjoy flexibility in management as compared to other countries and they can expand capital plant, develop new products and lay off surplus workers. Economic The economic crisis is one of the major constraints in local employment in the US labor market because as shown in the chart below, the unemployment rate has continued to rise up to 9.7% in 2010. Source: Bureau of Labor & Statistics.